Period 5 element - wikipedia Period 5 element Jump to : navigation , search Period 5 in the periodic table Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury ( element ) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Part of a series on the Periodic table Periodic table forms ( show ) 18 - column large cells 32 - column ( large cells ) Alternative forms Janet 's left step Beyond period 7 Fricke large cells Pyykkö Periodic table history ( show ) Dmitri Mendeleev predictions Discovery of elements Naming & etymology for places for scientists controversies ( in East Asia ) Systematic element names Sets of elements By periodic table structure ( hide ) Groups ( 1 -- 18 ) 1 ( alkali metals ) 2 ( alkaline earth metals ) 5 6 7 8 9 10 11 12 13 14 15 ( pnictogens ) 16 ( chalcogens ) 17 ( halogens ) 18 ( noble gases ) Periods ( 1 -- 7 ... ) 5 6 7 8 + Aufbau Fricke Pyykkö Blocks ( s , p , d , f , ... ) Atomic orbitals Aufbau principle By metallic classification ( show ) Metals alkali alkaline earth transition post-transition lanthanide actinide ( superactinide ) Metalloids dividing metals & nonmetals Nonmetals reactive nonmetals noble gases By other characteristics ( show ) Coinage metals Platinum - group metals Precious metals Refractory metals Heavy metals Light metals Native metals Noble metals Main - group elements Rare - earth elements Transuranium , transplutonium elements Major , minor & trans - actinides Elements List of chemical elements ( show ) by abundance ( in human body ) by atomic properties by isotope stability by annual production by symbol Properties of elements ( show ) Atomic weight Crystal structure Electron affinity configuration Electronegativity ( Allen , Pauling ) Goldschmidt classification Nutrition Valence Data pages for elements ( show ) Abundance Atomic radius Boiling point Critical point Density Elasticity Electrical resistivity Electron affinity / configuration Electronegativity Hardness Heat capacity / of fusion / of vaporization Ionization energy Melting point Oxidation state Speed of sound Thermal conductivity / expansion coefficient Vapor pressure Book Category Chemistry Portal A period 5 element is one of the chemical elements in the fifth row ( or period ) of the periodic table of the elements . The periodic table is laid out in rows to illustrate recurring ( periodic ) trends in the chemical behaviour of the elements as their atomic number increases : a new row is begun when chemical behaviour begins to repeat , meaning that elements with similar behaviour fall into the same vertical columns . The fifth period contains 18 elements , beginning with rubidium and ending with xenon . As a rule , period 5 elements fill their 5s shells first , then their 4d , and 5p shells , in that order ; however , there are exceptions , such as rhodium . Contents ( hide ) 1 Physical properties 2 Elements and their properties 3 s - block elements 3.1 Rubidium 3.2 Strontium 4 d - block elements 4.1 Yttrium 4.2 Zirconium 4.3 Niobium 4.4 Molybdenum 4.5 Technetium 4.6 Ruthenium 4.7 Rhodium 4.8 Palladium 4.9 Silver 4.10 Cadmium 5 p - block elements 5.1 Indium 5.2 Tin 5.3 Antimony 5.4 Tellurium 5.5 Iodine 5.6 Xenon 6 Biological role 7 Notes 8 References Physical properties ( edit ) This period contains technetium , one of the two elements until lead that has no stable isotopes ( along with promethium ) , as well as molybdenum and iodine , two of the heaviest elements with a known biological role , and Niobium has the largest magnetic known penetration depth of all the elements . Zirconium is one of the main components of zircon crystals , currently the oldest known minerals in the earth 's crust . Many later transition metals , such as rhodium , are very commonly used in jewelry due to the fact that they are incredibly shiny . This period is known to have a large number of exceptions to the Madelung rule . Elements and their properties ( edit ) Chemical element Chemical series Electron configuration 37 Rb Rubidium Alkali metal ( Kr ) 5s 38 Sr Strontium Alkaline earth metal ( Kr ) 5s 39 Y Yttrium Transition metal ( Kr ) 4d 5s 40 Zr Zirconium Transition metal ( Kr ) 4d 5s 41 Nb Niobium Transition metal ( Kr ) 4d 5s ( * ) 42 Mo Molybdenum Transition metal ( Kr ) 4d 5s ( * ) 43 Tc Technetium Transition metal ( Kr ) 4d 5s 44 Ru Ruthenium Transition metal ( Kr ) 4d 5s ( * ) 45 Rh Rhodium Transition metal ( Kr ) 4d 5s ( * ) 46 Pd Palladium Transition metal ( Kr ) 4d ( * ) 47 Ag Silver Transition metal ( Kr ) 4d 5s ( * ) 48 Cd Cadmium Post-transition metal ( Kr ) 4d 5s 49 In Indium Post-transition metal ( Kr ) 4d 5s 5p 50 Sn Tin Post-transition metal ( Kr ) 4d 5s 5p 51 Sb Antimony Metalloid ( Kr ) 4d 5s 5p 52 Te Tellurium Metalloid ( Kr ) 4d 5s 5p 53 Iodine Reactive nonmetal ( Kr ) 4d 5s 5p 54 Xe Xenon Noble gas ( Kr ) 4d 5s 5p ( * ) Exception to the Madelung rule S - block elements ( edit ) Rubidium ( edit ) Main article : rubidium Rubidium is the first element placed in period 5 . It is an alkali metal , the most reactive group in the periodic table , having properties and similarities with both other alkali metals and other period 5 elements . For example , rubidium has 5 electron shells , a property found in all other period 5 elements , whereas its electron configuration 's ending is similar to all other alkali metals : s . Rubidium also follows the trend of increasing reactivity as the atomic number increases in the alkali metals , for it is more reactive than potassium , but less so than caesium . In addition , both potassium and rubidium yield almost the same hue when ignited , so researchers must use different methods to differentiate between these two 1st group elements . Rubidium is very susceptible to oxidation in air , similar to most of the other alkali metals , so it readily transforms into rubidium oxide , a yellow solid with the chemical formula Rb O . Strontium ( edit ) Main article : strontium Strontium is the second element placed in the 5th period . It is an alkaline earth metal , a relatively reactive group , although not nearly as reactive as the alkali metals . Like rubidium , it has 5 electron shells or energy levels , and in accordance with the Madelung rule it has two electrons in its 5s subshell . Strontium is a soft metal and is extremely reactive upon contact with water . If it does come in contact with water , though , it will combine with the atoms of both oxygen and hydrogen to form strontium hydroxide and pure hydrogen gas which quickly diffuses in the air . In addition , strontium , like rubidium , oxidizes in air and turns a yellow color . When ignited , it will burn with a strong red flame . D. - block elements ( edit ) Yttrium ( edit ) Main article : Yttrium Yttrium ( / ˈɪtriəm / IT - ree - əm ) is a chemical element with symbol Y and atomic number 39 . It is a silvery - metallic transition metal chemically similar to the lanthanides and it has often been classified as a `` rare earth element '' . Yttrium is almost always found combined with the lanthanides in rare earth minerals and is never found in nature as a free element . Its only stable isotope , Y , is also its only naturally occurring isotope . In 1787 , Carl Axel Arrhenius found a new mineral near Ytterby in Sweden and named it ytterbite , after the village . Johan Gadolin discovered yttrium 's oxide in Arrhenius ' sample in 1789 , and Anders Gustaf Ekeberg named the new oxide yttria . Elemental yttrium was first isolated in 1828 by Friedrich Wöhler . The most important use of yttrium is in making phosphors , such as the red ones used in television set cathode ray tube ( CRT ) displays and in LEDs . Other uses include the production of electrodes , electrolytes , electronic filters , lasers and superconductors ; various medical applications ; and as traces in various materials to enhance their properties . Yttrium has no known biological role , and exposure to yttrium compounds can cause lung disease in humans . Zirconium ( edit ) Main article : Zirconium Zirconium ( / zərˈkoʊniəm / zər - KOH - nee - əm ) is a chemical element with the symbol Zr and atomic number 40 . The name of zirconium is taken from the mineral zircon . Its atomic mass is 91.224 . It is a lustrous , gray - white , strong transition metal that resembles titanium . Zirconium is mainly used as a refractory and opacifier , although minor amounts are used as alloying agent for its strong resistance to corrosion . Zirconium is obtained mainly from the mineral zircon , which is the most important form of zirconium in use . Zirconium forms a variety of inorganic and organometallic compounds such as zirconium dioxide and zirconocene dichloride , respectively . Five isotopes occur naturally , three of which are stable . Zirconium compounds have no biological role . Niobium ( edit ) Main article : Niobium Niobium / naɪˈoʊbiəm / ny - OH - bee - əm or columbium ( / kəˈlʌmbiəm / kə - LUM - bee - əm ) , is a chemical element with the symbol Nb and atomic number 41 . It is a soft , grey , ductile transition metal , which is often found in the pyrochlore mineral , the main commercial source for niobium , and columbite . The name comes from Greek mythology : Niobe , daughter of Tantalus . Niobium has physical and chemical properties similar to those of the element tantalum , and the two are therefore difficult to distinguish . The English chemist Charles Hatchett reported a new element similar to tantalum in 1801 , and named it columbium . In 1809 , the English chemist William Hyde Wollaston wrongly concluded that tantalum and columbium were identical . The German chemist Heinrich Rose determined in 1846 that tantalum ores contain a second element , which he named niobium . In 1864 and 1865 , a series of scientific findings clarified that niobium and columbium were the same element ( as distinguished from tantalum ) , and for a century both names were used interchangeably . The name of the element was officially adopted as niobium in 1949 . It was not until the early 20th century that niobium was first used commercially . Brazil is the leading producer of niobium and ferroniobium , an alloy of niobium and iron . Niobium is used mostly in alloys , the largest part in special steel such as that used in gas pipelines . Although alloys contain only a maximum of 0.1 % , that small percentage of niobium improves the strength of the steel . The temperature stability of niobium - containing superalloys is important for its use in jet and rocket engines . Niobium is used in various superconducting materials . These superconducting alloys , also containing titanium and tin , are widely used in the superconducting magnets of MRI scanners . Other applications of niobium include its use in welding , nuclear industries , electronics , optics , numismatics and jewelry . In the last two applications , niobium 's low toxicity and ability to be colored by anodization are particular advantages . Molybdenum ( edit ) Main article : Molybdenum Molybdenum ( / ˌmɒlɪbˈdiːnəm / MOL - ib - DEE - nəm , / məˈlɪbdɪnəm / mə - LIB - di - nəm ) , is a Group 6 chemical element with the symbol Mo and atomic number 42 . The name is from Neo-Latin Molybdaenum , from Ancient Greek Μόλυβδος molybdos , meaning lead , itself proposed as a loanword from Anatolian Luvian and Lydian languages , since its ores were confused with lead ores . The free element , which is a silvery metal , has the sixth - highest melting point of any element . It readily forms hard , stable carbides , and for this reason it is often used in high - strength steel alloys . Molybdenum does not occur as a free metal on Earth , but rather in various oxidation states in minerals . Industrially , molybdenum compounds are used in high - pressure and high - temperature applications , as pigments and catalysts . Molybdenum minerals have long been known , but the element was `` discovered '' ( in the sense of differentiating it as a new entity from the mineral salts of other metals ) in 1778 by Carl Wilhelm Scheele . The metal was first isolated in 1781 by Peter Jacob Hjelm . Most molybdenum compounds have low solubility in water , but the molybdate ion MoO is soluble and forms when molybdenum - containing minerals are in contact with oxygen and water . Technetium ( edit ) Main article : Technetium Technetium ( / tɛkˈniːʃiəm / tek - NEE - shee - əm ) is the chemical element with atomic number 43 and symbol Tc . It is the lowest atomic number element without any stable isotopes ; every form of it is radioactive . Nearly all technetium is produced synthetically and only minute amounts are found in nature . Naturally occurring technetium occurs as a spontaneous fission product in uranium ore or by neutron capture in molybdenum ores . The chemical properties of this silvery gray , crystalline transition metal are intermediate between rhenium and manganese . Many of technetium 's properties were predicted by Dmitri Mendeleev before the element was discovered . Mendeleev noted a gap in his periodic table and gave the undiscovered element the provisional name ekamanganese ( Em ) . In 1937 technetium ( specifically the technetium - 97 isotope ) became the first predominantly artificial element to be produced , hence its name ( from the Greek τεχνητός , meaning `` artificial '' ) . Its short - lived gamma ray - emitting nuclear isomer -- technetium - 99m -- is used in nuclear medicine for a wide variety of diagnostic tests . Technetium - 99 is used as a gamma ray - free source of beta particles . Long - lived technetium isotopes produced commercially are by - products of fission of uranium - 235 in nuclear reactors and are extracted from nuclear fuel rods . Because no isotope of technetium has a half - life longer than 4.2 million years ( technetium - 98 ) , its detection in red giants in 1952 , which are billions of years old , helped bolster the theory that stars can produce heavier elements . Ruthenium ( edit ) Main article : Ruthenium Ruthenium ( / ruːˈθiːniəm / roo - THEE - nee - əm ) is a chemical element with symbol Ru and atomic number 44 . It is a rare transition metal belonging to the platinum group of the periodic table . Like the other metals of the platinum group , ruthenium is inert to most chemicals . The Russian scientist Karl Ernst Claus discovered the element in 1844 and named it after Ruthenia , the Latin word for Rus ' . Ruthenium usually occurs as a minor component of platinum ores and its annual production is only about 12 tonnes worldwide . Most ruthenium is used for wear - resistant electrical contacts and the production of thick - film resistors . A minor application of ruthenium is its use in some platinum alloys . Rhodium ( edit ) Main article : Rhodium Rhodium ( / ˈroʊdiəm / ROH - dee - əm ) is a chemical element that is a rare , silvery - white , hard , and chemically inert transition metal and a member of the platinum group . It has the chemical symbol Rh and atomic number 45 . It is composed of only one isotope , Rh . Naturally occurring rhodium is found as the free metal , alloyed with similar metals , and never as a chemical compound . It is one of the rarest precious metals and one of the most costly ( gold has since taken over the top spot of cost per ounce ) . Rhodium is a so - called noble metal , resistant to corrosion , found in platinum - or nickel ores together with the other members of the platinum group metals . It was discovered in 1803 by William Hyde Wollaston in one such ore , and named for the rose color of one of its chlorine compounds , produced after it reacted with the powerful acid mixture aqua regia . The element 's major use ( about 80 % of world rhodium production ) is as one of the catalysts in the three - way catalytic converters of automobiles . Because rhodium metal is inert against corrosion and most aggressive chemicals , and because of its rarity , rhodium is usually alloyed with platinum or palladium and applied in high - temperature and corrosion - resistive coatings . White gold is often plated with a thin rhodium layer to improve its optical impression while sterling silver is often rhodium plated for tarnish resistance . Rhodium detectors are used in nuclear reactors to measure the neutron flux level . Palladium ( edit ) Main article : Palladium Palladium ( / pəˈleɪdiəm / pə - LAY - dee - əm ) is a chemical element with the chemical symbol Pd and an atomic number of 46 . It is a rare and lustrous silvery - white metal discovered in 1803 by William Hyde Wollaston . He named it after the asteroid Pallas , which was itself named after the epithet of the Greek goddess Athena , acquired by her when she slew Pallas . Palladium , platinum , rhodium , ruthenium , iridium and osmium form a group of elements referred to as the platinum group metals ( PGMs ) . These have similar chemical properties , but palladium has the lowest melting point and is the least dense of them . The unique properties of palladium and other platinum group metals account for their widespread use . A quarter of all goods manufactured today either contain PGMs or have a significant part in their manufacturing process played by PGMs . Over half of the supply of palladium and its congener platinum goes into catalytic converters , which convert up to 90 % of harmful gases from auto exhaust ( hydrocarbons , carbon monoxide , and nitrogen dioxide ) into less - harmful substances ( nitrogen , carbon dioxide and water vapor ) . Palladium is also used in electronics , dentistry , medicine , hydrogen purification , chemical applications , and groundwater treatment . Palladium plays a key role in the technology used for fuel cells , which combine hydrogen and oxygen to produce electricity , heat , and water . Ore deposits of palladium and other PGMs are rare , and the most extensive deposits have been found in the norite belt of the Bushveld Igneous Complex covering the Transvaal Basin in South Africa , the Stillwater Complex in Montana , United States , the Thunder Bay District of Ontario , Canada , and the Norilsk Complex in Russia . Recycling is also a source of palladium , mostly from scrapped catalytic converters . The numerous applications and limited supply sources of palladium result in the metal attracting considerable investment interest . Silver ( edit ) Main article : Silver Silver ( / ˈsɪlvər / SIL - vər ) is a metallic chemical element with the chemical symbol Ag ( Latin : argentum , from the Indo - European root * arg - for `` grey '' or `` shining '' ) and atomic number 47 . A soft , white , lustrous transition metal , it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal . The metal occurs naturally in its pure , free form ( native silver ) , as an alloy with gold and other metals , and in minerals such as argentite and chlorargyrite . Most silver is produced as a byproduct of copper , gold , lead , and zinc refining . Silver has long been valued as a precious metal , and it is used to make ornaments , jewelry , high - value tableware , utensils ( hence the term silverware ) , and currency coins . Today , silver metal is also used in electrical contacts and conductors , in mirrors and in catalysis of chemical reactions . Its compounds are used in photographic film , and dilute silver nitrate solutions and other silver compounds are used as disinfectants and microbiocides . While many medical antimicrobial uses of silver have been supplanted by antibiotics , further research into clinical potential continues . Cadmium ( edit ) Main article : Cadmium Cadmium ( / ˈkædmiəm / KAD - mee - əm ) is a chemical element with the symbol Cd and atomic number 48 . This soft , bluish - white metal is chemically similar to the two other stable metals in group 12 , zinc and mercury . Like zinc , it prefers oxidation state + 2 in most of its compounds and like mercury it shows a low melting point compared to transition metals . Cadmium and its congeners are not always considered transition metals , in that they do not have partly filled d or f electron shells in the elemental or common oxidation states . The average concentration of cadmium in the Earth 's crust is between 0.1 and 0.5 parts per million ( ppm ) . It was discovered in 1817 simultaneously by Stromeyer and Hermann , both in Germany , as an impurity in zinc carbonate . Cadmium occurs as a minor component in most zinc ores and therefore is a byproduct of zinc production . It was used for a long time as a pigment and for corrosion resistant plating on steel while cadmium compounds were used to stabilize plastic . With the exception of its use in nickel -- cadmium batteries and cadmium telluride solar panels , the use of cadmium is generally decreasing . These declines have been due to competing technologies , cadmium 's toxicity in certain forms and concentration and resulting regulations . P - block elements ( edit ) Indium ( edit ) Main article : Indium Indium ( / ˈɪndiəm / IN - dee - əm ) is a chemical element with the symbol In and atomic number 49 . This rare , very soft , malleable and easily fusible other metal is chemically similar to gallium and thallium , and shows the intermediate properties between these two . Indium was discovered in 1863 and named for the indigo blue line in its spectrum that was the first indication of its existence in zinc ores , as a new and unknown element . The metal was first isolated in the following year . Zinc ores continue to be the primary source of indium , where it is found in compound form . Very rarely the element can be found as grains of native ( free ) metal , but these are not of commercial importance . Indium 's current primary application is to form transparent electrodes from indium tin oxide in liquid crystal displays and touchscreens , and this use largely determines its global mining production . It is widely used in thin - films to form lubricated layers ( during World War II it was widely used to coat bearings in high - performance aircraft ) . It is also used for making particularly low melting point alloys , and is a component in some lead - free solders . Indium is not known to be used by any organism . In a similar way to aluminium salts , indium ( III ) ions can be toxic to the kidney when given by injection , but oral indium compounds do not have the chronic toxicity of salts of heavy metals , probably due to poor absorption in basic conditions . Radioactive indium - 111 ( in very small amounts on a chemical basis ) is used in nuclear medicine tests , as a radiotracer to follow the movement of labeled proteins and white blood cells in the body . Tin ( edit ) Main article : Tin Tin ( / ˈtɪn / TIN ) is a chemical element with the symbol Sn ( for Latin : stannum ) and atomic number 50 . It is a main group metal in group 14 of the periodic table . Tin shows chemical similarity to both neighboring group 14 elements , germanium and lead and has two possible oxidation states , + 2 and the slightly more stable + 4 . Tin is the 49th most abundant element and has , with 10 stable isotopes , the largest number of stable isotopes in the periodic table . Tin is obtained chiefly from the mineral cassiterite , where it occurs as tin dioxide , SnO . This silvery , malleable other metal is not easily oxidized in air and is used to coat other metals to prevent corrosion . The first alloy , used in large scale since 3000 BC , was bronze , an alloy of tin and copper . After 600 BC pure metallic tin was produced . Pewter , which is an alloy of 85 -- 90 % tin with the remainder commonly consisting of copper , antimony and lead , was used for tableware from the Bronze Age until the 20th century . In modern times tin is used in many alloys , most notably tin / lead soft solders , typically containing 60 % or more of tin . Another large application for tin is corrosion - resistant tin plating of steel . Because of its low toxicity , tin - plated metal is also used for food packaging , giving the name to tin cans , which are made mostly of steel . Antimony ( edit ) Main article : Antimony Antimony ( / ænˈtɪmoʊni / ann - TIM - oh - nee , / ˈæntəˌmoʊni / AN - tə - moh - nee ; Latin : stibium ) is a toxic chemical element with the symbol Sb and an atomic number of 51 . A lustrous grey metalloid , it is found in nature mainly as the sulfide mineral stibnite ( Sb S ) . Antimony compounds have been known since ancient times and were used for cosmetics , metallic antimony was also known but mostly identified as lead . For some time China has been the largest producer of antimony and its compounds , with most production coming from the Xikuangshan Mine in Hunan . Antimony compounds are prominent additives for chlorine and bromine containing fire retardants found in many commercial and domestic products . The largest application for metallic antimony is as alloying material for lead and tin . It improves the properties of the alloys which are used as in solders , bullets and ball bearings . An emerging application is the use of antimony in microelectronics . Tellurium ( edit ) Main article : Tellurium Tellurium ( / tɪˈljuːriəm / ti - LEW - ree - əm , / tɛ - / teh - ) is a chemical element that has the symbol Te and atomic number 52 . A brittle , mildly toxic , rare , silver - white metalloid which looks similar to tin , tellurium is chemically related to selenium and sulfur . It is occasionally found in native form , as elemental crystals . Tellurium is far more common in the universe than on Earth . Its extreme rarity in the Earth 's crust , comparable to that of platinum , is partly due to its high atomic number , but also due to its formation of a volatile hydride which caused the element to be lost to space as a gas during the hot nebular formation of the planet . Tellurium was discovered in Transylvania ( today part of Romania ) in 1782 by Franz - Joseph Müller von Reichenstein in a mineral containing tellurium and gold . Martin Heinrich Klaproth named the new element in 1798 after the Latin word for `` earth '' , tellus . Gold telluride minerals ( responsible for the name of Telluride , Colorado ) are the most notable natural gold compounds . However , they are not a commercially significant source of tellurium itself , which is normally extracted as by - product of copper and lead production . Tellurium is commercially primarily used in alloys , foremost in steel and copper to improve machinability . Applications in solar panels and as a semiconductor material also consume a considerable fraction of tellurium production . Iodine ( edit ) Main article : Iodine Iodine is a chemical element with the symbol I and atomic number 53 . The name is pronounced / ˈaɪ. oʊ daɪn / EYE - oh - dyne , / ˈaɪ. oʊ dɪn / EYE - oh - din , or / ˈaɪ. oʊ diːn / EYE - oh - deen in both American and British English . The name is from Greek ἰοειδής ioeidēs , meaning violet or purple , due to the color of elemental iodine vapor . Iodine and its compounds are primarily used in nutrition , and industrially in the production of acetic acid and certain polymers . Iodine 's relatively high atomic number , low toxicity , and ease of attachment to organic compounds have made it a part of many X-ray contrast materials in modern medicine . Iodine has only one stable isotope . A number of iodine radioisotopes are also used in medical applications . Iodine is found on Earth mainly as the highly water - soluble iodide I , which concentrates it in oceans and brine pools . Like the other halogens , free iodine occurs mainly as a diatomic molecule I , and then only momentarily after being oxidized from iodide by an oxidant like free oxygen . In the universe and on Earth , iodine 's high atomic number makes it a relatively rare element . However , its presence in ocean water has given it a role in biology ( see below ) . Xenon ( edit ) Main article : Xenon Xenon is a chemical element with the symbol Xe and atomic number 54 . The element name is pronounced / ˈzɛnɒn / ZEN - on , / ˈziːnɒn / ZEE - non . A colorless , heavy , odorless noble gas , xenon occurs in the Earth 's atmospherein trace amounts . Although generally unreactive , xenon can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate , the first noble gas compound to be synthesized . Naturally occurring xenon consists of nine stable isotopes . There are also over 40 unstable isotopes that undergo radioactive decay . The isotope ratios of xenon are an important tool for studying the early history of the Solar System . Radioactive xenon - 135 is produced from iodine - 135 as a result of nuclear fission , and it acts as the most significant neutron absorber in nuclear reactors . Xenon is used in flash lamps and arc lamps , and as a general anesthetic . The first excimer laser design used a xenon dimer molecule ( Xe ) as its lasing medium , and the earliest laser designs used xenon flash lamps as pumps . Xenon is also being used to search for hypothetical weakly interacting massive particles and as the propellant for ion thrusters in spacecraft . Biological role ( edit ) Rubidium , strontium , yttrium , zirconium , and niobium have no biological role . Yttrium can cause lung disease in humans . Molybdenum - containing enzymes are used as catalysts by some bacteria to break the chemical bond in atmospheric molecular nitrogen , allowing biological nitrogen fixation . At least 50 molybdenum - containing enzymes are now known in bacteria and animals , though only the bacterial and cyanobacterial enzymes are involved in nitrogen fixation . Owing to the diverse functions of the remainder of the enzymes , molybdenum is a required element for life in higher organisms ( eukaryotes ) , though not in all bacteria . Technetium , ruthenium , rhodium , palladium , silver , tin , and antimony have no biological role . Although cadmium has no known biological role in higher organisms , a cadmium - dependent carbonic anhydrase has been found in marine diatoms . Indium has no biological role and can be toxic as well as Antimony . Tellurium has no biological role , although fungi can incorporate it in place of sulfur and selenium into amino acids such as tellurocysteine and telluromethionine . In humans , tellurium is partly metabolized into dimethyl telluride , ( CH ) Te , a gas with a garlic - like odor which is exhaled in the breath of victims of tellurium toxicity or exposure . Iodine is the heaviest essential element utilized widely by life in biological functions ( only tungsten , employed in enzymes by a few species of bacteria , is heavier ) . Iodine 's rarity in many soils , due to initial low abundance as a crust - element , and also leaching of soluble iodide by rainwater , has led to many deficiency problems in land animals and inland human populations . Iodine deficiency affects about two billion people and is the leading preventable cause of intellectual disabilities . Iodine is required by higher animals , which use it to synthesize thyroid hormones , which contain the element . Because of this function , radioisotopes of iodine are concentrated in the thyroid gland along with nonradioactive iodine . The radioisotope iodine - 131 , which has a high fission product yield , concentrates in the thyroid , and is one of the most carcinogenic of nuclear fission products . Xenon has no biological role , and is used as a general anaesthetic . Notes ( edit ) References ( edit ) Jump up ^ `` Iodine '' . 3rd1000.com . Retrieved 2012 - 08 - 13 . Jump up ^ `` WebElements Periodic Table of the Elements Molybdenum biological information '' . Webelements.com . Retrieved 2012 - 08 - 13 . Jump up ^ Gray , Theodore ( 2009 ) . The Elements : A Visual Exploration of Every Known Atom in the Universe . New York : Black Dog & Leventhal Publishers . ISBN 978 - 1 - 57912 - 814 - 2 . Jump up ^ `` Periodic Table of Elements : Rubidium -- Rb '' . EnvironmentalChemistry.com. 1995 - 10 - 22 . Retrieved 2012 - 08 - 13 . Jump up ^ `` Flame Tests '' . Webmineral.com . Retrieved 2012 - 08 - 13 . Jump up ^ `` Reactions of the Group 1 elements with oxygen and chlorine '' . Chemguide.co.uk . Retrieved 2012 - 08 - 13 . Jump up ^ IUPAC contributors ( 2005 ) . Edited by NG Connelly and T Damhus ( with RM Hartshorn and AT Hutton ) , ed . Nomenclature of Inorganic Chemistry : IUPAC Recommendations 2005 ( PDF ) . RSC Publishing . p. 51 . ISBN 0 - 85404 - 438 - 8 . Archived from the original ( PDF ) on 2009 - 03 - 04 . Retrieved 2007 - 12 - 17 . CS1 maint : Extra text : editors list ( link ) Jump up ^ Van der Krogt 2005 Jump up ^ CRC contributors ( 2007 -- 2008 ) . `` Yttrium '' . In Lide , David R. CRC Handbook of Chemistry and Physics. 4 . New York : CRC Press . p. 41 . ISBN 978 - 0 - 8493 - 0488 - 0 . Jump up ^ Cotton , Simon A. ( 2006 - 03 - 15 ) . `` Encyclopedia of Inorganic Chemistry '' . doi : 10.1002 / 0470862106. ia211 . ISBN 0 - 470 - 86078 - 2 . chapter = ignored ( help ) Jump up ^ OSHA contributors ( 2007 - 01 - 11 ) . `` Occupational Safety and Health Guideline for Yttrium and Compounds '' . United States Occupational Safety and Health Administration . Archived from the original on 2013 - 03 - 02 . Retrieved 2008 - 08 - 03 . ( public domain text ) Jump up ^ Melchert , Craig . `` Greek mólybdos as a Loanword from Lydian '' ( PDF ) . University of North Carolina at Chapel Hill . Archived from the original ( PDF ) on 2008 - 10 - 12 . Retrieved 2011 - 04 - 23 . Jump up ^ editor - in - chief David R. Lide. ( 1994 ) . `` Molybdenum '' . In Lide , David R. CRC Handbook of Chemistry and Physics. 4 . Chemical Rubber Publishing Company . p. 18 . ISBN 0 - 8493 - 0474 - 1 . CS1 maint : Extra text : authors list ( link ) Jump up ^ `` Palladium '' . International Platinum Group Metals Association . Archived from the original on 2010 - 04 - 20 . Jump up ^ `` Cadmium '' . Kirk - Othmer Encyclopedia of Chemical Technology . 5 ( 4th ed . ) . New York : John Wiley & Sons . 1994 . Jump up ^ Iodine . Merriam - Webster Dictionary . Retrieved on 2011 - 12 - 23 . Jump up ^ Iodine -- Oxford Dictionaries Online ( World English ) ) . Retrieved on 2011 - 12 - 23 . Jump up ^ All three pronunciations are used in both British and American English , but / ˈaɪ. oʊ diːn / EYE - oh - deen is the most common British one and / ˈaɪ. oʊ daɪn / EYE - oh - dyne is the most common American one . Jump up ^ Online Etymology Dictionary , s.v. iodine . Retrieved 2012 - 02 - 07 . Jump up ^ Staff ( 2007 ) . `` Xenon '' . Columbia Electronic Encyclopedia ( 6th ed . ) . Columbia University Press . Retrieved 2007 - 10 - 23 . Jump up ^ Husted , Robert ; Boorman , Mollie ( December 15 , 2003 ) . `` Xenon '' . Los Alamos National Laboratory , Chemical Division . Retrieved 2007 - 09 - 26 . Jump up ^ Rabinovich , Viktor Abramovich ; Vasserman , A.A. ; Nedostup , V.I. ; Veksler , L.S. ( 1988 ) . Thermophysical properties of neon , argon , krypton , and xenon ( English - language ed . ) . Washington , DC : Hemisphere Publishing Corp . ISBN 0 - 89116 - 675 - 0 . Retrieved 2009 - 04 - 02 . -- National Standard Reference Data Service of the USSR . Volume 10 . Jump up ^ Freemantel , Michael ( August 25 , 2003 ) . `` Chemistry at its Most Beautiful '' ( PDF ) . Chemical & Engineering News . Archived from the original ( PDF ) on January 6 , 2016 . Retrieved 2007 - 09 - 13 . Jump up ^ Kaneoka , Ichiro ( 1998 ) . `` Xenon 's Inside Story '' . Science . 280 ( 5365 ) : 851 -- 852 . doi : 10.1126 / science. 280.5365. 851b . Jump up ^ Stacey , Weston M. ( 2007 ) . Nuclear Reactor Physics . Wiley - VCH . p. 213 . ISBN 3 - 527 - 40679 - 4 . Jump up ^ Anonymous . `` History '' . Millisecond Cinematography . Archived from the original on 2006 - 08 - 22 . Retrieved 2007 - 11 - 07 . Jump up ^ Mellor , David ( 2000 ) . Sound Person 's Guide to Video . Focal Press . p. 186 . ISBN 0 - 240 - 51595 - 1 . Jump up ^ Sanders , Robert D. ; Ma , Daqing ; Maze , Mervyn ( 2005 ) . `` Xenon : elemental anaesthesia in clinical practice '' . British Medical Bulletin . 71 ( 1 ) : 115 -- 35 . doi : 10.1093 / bmb / ldh034 . PMID 15728132 . Jump up ^ Basov , N.G. ; Danilychev , V.A. ; Popov , Yu . M. ( 1971 ) . `` Stimulated Emission in the Vacuum Ultraviolet Region '' . Soviet Journal of Quantum Electronics . 1 ( 1 ) : 18 -- 22 . Bibcode : 1971QuEle ... 1 ... 18B . doi : 10.1070 / QE1971v001n01ABEH003011 . Jump up ^ Toyserkani , E. ; Khajepour , A. ; Corbin , S. ( 2004 ) . Laser Cladding . CRC Press . p. 48 . ISBN 0 - 8493 - 2172 - 7 . Jump up ^ Ball , Philip ( May 1 , 2002 ) . `` Xenon outs WIMPs '' . Nature . Retrieved 2007 - 10 - 08 . Jump up ^ Saccoccia , G. ; del Amo , J.G. ; Estublier , D. ( August 31 , 2006 ) . `` Ion engine gets SMART - 1 to the Moon '' . ESA . Retrieved 2007 - 10 - 01 . Jump up ^ Ramadan , Shadia E. ; Razak , A.A. ; Ragab , A.M. ; El - Meleigy , M. ( 1989 ) . `` Incorporation of tellurium into amino acids and proteins in a tellurium - tolerant fungi '' . Biological Trace Element Research . 20 ( 3 ) : 225 -- 32 . doi : 10.1007 / BF02917437 . PMID 2484755 . Jump up ^ McNeil , Donald G. Jr ( 2006 - 12 - 16 ) . `` In Raising the World 's I.Q. , the Secret 's in the Salt '' . New York Times . Retrieved 2008 - 12 - 04 . Periodic table Periodic table forms Standard 18 - column 18 - column , large cells 32 - column , large cells Alternative Alternatives Janet 's left step table Extended Extension beyond the 7th period Fricke model large cells Pyykkö model Sets of elements By periodic table structure Groups 1 ( Alkali metals ) 2 ( Alkaline earth metals ) 5 6 7 8 9 10 11 12 13 14 15 ( Pnictogens ) 16 ( Chalcogens ) 17 ( Halogens ) 18 ( Noble gases ) Periods 5 6 7 8 + Aufbau Fricke Pyykkö Blocks s - block p - block d - block f - block g - block Aufbau principle By metallicity Metals Alkali metals Alkaline earth metals Lanthanides Actinides Transition metals Post-transition metals Metalloids Lists of metalloids by source Dividing line Nonmetals Reactive nonmetals Noble gases Other sets Nutritional elements Platinum - group metals ( PGM ) Rare - earth elements Refractory metals Precious metals Coinage metals Noble metal Heavy metals Native metals Transuranium elements Transactinide elements Major actinides Minor actinides Elements Lists By : Abundance ( in humans ) Atomic properties Nuclear stability Production Symbol Properties Atomic weight Crystal structure Electron affinity Electron configuration Electronegativity Allen Pauling Goldschmidt classification Maximum valence Data pages Abundance Atomic radius Boiling point Critical point Density Elasticity Electrical resistivity Electron affinity Electron configuration Electronegativity Hardness Heat capacity Heat of fusion Heat of vaporization Ionization energy Melting point Oxidation state Speed of sound Thermal conductivity Thermal expansion coefficient Vapor pressure History Element discoveries Mendeleev 's predictions Naming Etymology controversies places scientists in East Asia See also IUPAC nomenclature systematic element name Trivial name Dmitri Mendeleev Book Category Chemistry Portal ( hide ) Periodic table ( Large cells ) 5 6 7 8 9 10 11 12 13 14 15 16 17 18 He Li Be Ne Na Mg Al Si Cl Ar Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te Xe 6 Cs Ba La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf Ta Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 7 Fr Ra Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og Alkali metal Alkaline earth metal Lanthanide Actinide Transition metal Post -  transition metal Metalloid Reactive nonmetal Noble gas Unknown chemical properties Retrieved from `` https://en.wikipedia.org/w/index.php?title=Period_5_element&oldid=838195027 '' Categories : Periods ( periodic table ) Hidden categories : CS1 maint : Extra text : editors list CS1 errors : chapter ignored CS1 maint : Extra text : authors list Articles containing Ancient Greek - language text Articles containing Greek - language text Articles containing Latin - language text Pages containing element color directly Talk Contents About Wikipedia Aragonés Asturianu Azərbaycanca বাংলা भोजपुरी Català Čeština Cymraeg Dansk Deutsch Español Esperanto Euskara فارسی Français 한국어 Bahasa Indonesia Interlingua Italiano Lumbaart Македонски Bahasa Melayu Nederlands 日本 語 Nordfriisk ਪੰਜਾਬੀ Polski Русский Simple English Slovenčina Српски / srpski Srpskohrvatski / српскохрватски Suomi தமிழ் ไทย Türkçe Українська Tiếng Việt 中文 31 more Edit links This page was last edited on 25 April 2018 , at 14 : 21 . 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Question: the atomic number of indium which belongs to 5th period is


Photosynthetic efficiency - wikipedia Photosynthetic efficiency Jump to : navigation , search The photosynthetic efficiency is the fraction of light energy converted into chemical energy during photosynthesis in plants and algae . Photosynthesis can be described by the simplified chemical reaction 6H O + 6CO + energy → C H O + 6O where C H O is glucose ( which is subsequently transformed into other sugars , cellulose , lignin , and so forth ) . The value of the photosynthetic efficiency is dependent on how light energy is defined -- it depends on whether we count only the light that is absorbed , and on what kind of light is used ( see Photosynthetically active radiation ) . It takes eight ( or perhaps 10 or more ) photons to utilize one molecule of CO . The Gibbs free energy for converting a mole of CO to glucose is 114 kcal , whereas eight moles of photons of wavelength 600 nm contains 381 kcal , giving a nominal efficiency of 30 % . However , photosynthesis can occur with light up to wavelength 720 nm so long as there is also light at wavelengths below 680 nm to keep Photosystem II operating ( see Chlorophyll ) . Using longer wavelengths means less light energy is needed for the same number of photons and therefore for the same amount of photosynthesis . For actual sunlight , where only 45 % of the light is in the photosynthetically active wavelength range , the theoretical maximum efficiency of solar energy conversion is approximately 11 % . In actuality , however , plants do not absorb all incoming sunlight ( due to reflection , respiration requirements of photosynthesis and the need for optimal solar radiation levels ) and do not convert all harvested energy into biomass , which results in an overall photosynthetic efficiency of 3 to 6 % of total solar radiation . If photosynthesis is inefficient , excess light energy must be dissipated to avoid damaging the photosynthetic apparatus . Energy can be dissipated as heat ( non-photochemical quenching ) , or emitted as chlorophyll fluorescence . Contents ( hide ) 1 Typical efficiencies 1.1 Plants 1.2 Algae and other monocellular organisms 1.2. 1 Worldwide figures 2 Efficiencies of various biofuel crops 3 C3 vs. C4 and CAM plants 4 See also 5 References Typical efficiencies ( edit ) Plants ( edit ) Quoted values sunlight - to - biomass efficiency Plant Efficiency Plants , typical 0.1 % 0.2 -- 2 % Typical crop plants 1 -- 2 % The following is a breakdown of the energetics of the photosynthesis process from Photosynthesis by Hall and Rao : Starting with the solar spectrum falling on a leaf , 47 % lost due to photons outside the 400 -- 700 nm active range ( chlorophyll utilizes photons between 400 and 700 nm , extracting the energy of one 700 nm photon from each one ) 30 % of the in - band photons are lost due to incomplete absorption or photons hitting components other than chloroplasts 24 % of the absorbed photon energy is lost due to degrading short wavelength photons to the 700 nm energy level 68 % of the utilized energy is lost in conversion into d - glucose 35 -- 45 % of the glucose is consumed by the leaf in the processes of dark and photo respiration Stated another way : 100 % sunlight → non-bioavailable photons waste is 47 % , leaving 53 % ( in the 400 -- 700 nm range ) → 30 % of photons are lost due to incomplete absorption , leaving 37 % ( absorbed photon energy ) → 24 % is lost due to wavelength - mismatch degradation to 700 nm energy , leaving 28.2 % ( sunlight energy collected by chlorophyl ) → 32 % efficient conversion of ATP and NADPH to d - glucose , leaving 9 % ( collected as sugar ) → 35 -- 40 % of sugar is recycled / consumed by the leaf in dark and photo - respiration , leaving 5.4 % net leaf efficiency . Many plants lose much of the remaining energy on growing roots . Most crop plants store ~ 0.25 % to 0.5 % of the sunlight in the product ( corn kernels , potato starch , etc . ) . Photosynthesis increases linearly with light intensity at low intensity , but at higher intensity this is no longer the case ( see Photosynthesis - irradiance curve ) . Above about 10,000 lux or ~ 100 watts / square meter the rate no longer increases . Thus , most plants can only utilize ~ 10 % of full mid-day sunlight intensity . This dramatically reduces average achieved photosynthetic efficiency in fields compared to peak laboratory results . However , real plants ( as opposed to laboratory test samples ) have lots of redundant , randomly oriented leaves . This helps to keep the average illumination of each leaf well below the mid-day peak enabling the plant to achieve a result closer to the expected laboratory test results using limited illumination . Only if the light intensity is above a plant specific value , called the compensation point the plant assimilates more carbon and releases more oxygen by photosynthesis than it consumes by cellular respiration for its own current energy demand . Photosynthesis measurement systems are not designed to directly measure the amount of light absorbed by the leaf . Nevertheless , the light response curves that the class produces do allow comparisons in photosynthetic efficiency between plants . Algae and other monocellular organisms ( edit ) From a 2010 study by the University of Maryland , photosynthesizing Cyanobacteria have been shown to be a significant species in the global carbon cycle , accounting for 20 -- 30 % of Earth 's photosynthetic productivity and convert solar energy into biomass - stored chemical energy at the rate of ~ 450 TW . Worldwide figures ( edit ) According to the cyanobacteria study above , this means the total photosynthetic productivity of earth is between ~ 1500 -- 2250 TW , or 4.73 -- 7.10 x 10 J ( 47,300 -- 71,000 exajoules ) per year . Using this source 's figure of 178,000 TW of solar energy hitting the Earth 's surface , the total photosynthetic efficiency of the planet is 0.84 % to 1.26 % ( see also Earth 's energy budget ) . Efficiencies of various biofuel crops ( edit ) Popular choices for plant biofuels include : oil palm , soybean , castor oil , sunflower oil , safflower oil , corn ethanol , and sugar cane ethanol . An analysis of a proposed Hawaiian oil palm plantation claimed to yield 600 gallons of biodiesel per acre per year . That comes to 2835 watts per acre or 0.7 W / m . Typical insolation in Hawaii is around 5.5 kWh / ( m day ) or 230 W / m . For this particular oil palm plantation , if it delivered the claimed 600 gallons of biodiesel per acre per year , would be converting 0.3 % of the incident solar energy to chemical fuel . Total photosynthetic efficiency would include more than just the biodiesel oil , so this 0.3 % number is something of a lower bound . Contrast this with a typical photovoltaic installation , which would produce an average of roughly 22 W / m ( roughly 10 % of the average insolation ) , throughout the year . Furthermore , the photovoltaic panels would produce electricity , which is a high - quality form of energy , whereas converting the biodiesel into mechanical energy entails the loss of a large portion of the energy . On the other hand , a liquid fuel is much more convenient for a vehicle than electricity , which has to be stored in heavy , expensive batteries . Most crop plants store ~ 0.25 % to 0.5 % of the sunlight in the product ( corn kernels , potato starch , etc . ) , sugar cane is exceptional in several ways to yield peak storage efficiencies of ~ 8 % . Ethanol fuel in Brazil has a calculation that results in : `` Per hectare per year , the biomass produced corresponds to 0.27 TJ . This is equivalent to 0.86 W / m . Assuming an average insolation of 225 W / m , the photosynthetic efficiency of sugar cane is 0.38 % . '' Sucrose accounts for little more than 30 % of the chemical energy stored in the mature plant ; 35 % is in the leaves and stem tips , which are left in the fields during harvest , and 35 % are in the fibrous material ( bagasse ) left over from pressing . C3 vs. C4 and CAM plants ( edit ) C3 plants use the Calvin cycle to fix carbon . C4 plants use a modified Calvin cycle in which they separate Ribulose - 1 , 5 - bisphosphate carboxylase oxygenase ( RuBisCO ) from atmospheric oxygen , fixing carbon in their mesophyll cells and using oxaloacetate and malate to ferry the fixed carbon to RuBisCO and the rest of the Calvin cycle enzymes isolated in the bundle - sheath cells . The intermediate compounds both contain four carbon atoms , which gives C4 . In Crassulacean acid metabolism ( CAM ) , time isolates functioning RuBisCo ( and the other Calvin cycle enzymes ) from high oxygen concentrations produced by photosynthesis , in that O is evolved during the day , and allowed to dissipate then , while at night atmospheric CO is taken up and stored as malic or other acids . During the day , CAM plants close stomata and use stored acids as carbon sources for sugar , etc. production . The C3 pathway requires 18 ATP for the synthesis of one molecule of glucose while the C4 pathway requires 20 ATP . Despite this reduced ATP efficiency , C4 is an evolutionary advancement , adapted to areas of high levels of light , where the reduced ATP efficiency is more than offset by the use of increased light . The ability to thrive despite restricted water availability maximizes the ability to use available light . The simpler C3 cycle which operates in most plants is adapted to wetter darker environments , such as many northern latitudes. . Corn , sugar cane , and sorghum are C4 plants . These plants are economically important in part because of their relatively high photosynthetic efficiencies compared to many other crops . Pineapple is a CAM plant . See also ( edit ) Energy conversion efficiency FLEX ( satellite ) Phototroph Photosynthetically active radiation References ( edit ) ^ Jump up to : Renewable biological systems for unsustainable energy production . FAO Agricultural Services Bulletins ( 1997 ) . Jump up ^ Lubert Stryer ( 1981 ) . Biochemistry ( 2nd ed . ) . p. 448 . ISBN 0 - 7167 - 1226 - 1 . ^ Jump up to : Govindjee , What is photosynthesis ? Jump up ^ The Green Solar Collector ; converting sunlight into algal biomass Wageningen University project ( 2005 -- 2008 ) ^ Jump up to : David Oakley Hall ; K.K. Rao ; Institute of Biology ( 1999 ) . Photosynthesis . Cambridge University Press . ISBN 978 - 0 - 521 - 64497 - 6 . Retrieved 3 November 2011 . ^ Jump up to : Pisciotta JM , Zou Y , Baskakov IV ( 2010 ) . `` Light - Dependent Electrogenic Activity of Cyanobacteria '' . PLoS ONE . 5 ( 5 ) : e10821 . doi : 10.1371 / journal. pone. 0010821 . PMC 2876029 . PMID 20520829 . Jump up ^ Biodiesel Fuel . Ag.ndsu.edu ... Retrieved on 2011 - 11 - 03 . Jump up ^ PVWATTS : Hawaii . Rredc.nrel.gov . Retrieved on 2011 - 11 - 03 . Jump up ^ NREL : In My Backyard ( IMBY ) Home Page . Nrel.gov ( 2010 - 12 - 23 ) . Retrieved on 2011 - 11 - 03 . Ecology : Modelling ecosystems : Trophic components General Abiotic component Abiotic stress Behaviour Biogeochemical cycle Biomass Biotic component Biotic stress Carrying capacity Competition Ecosystem Ecosystem ecology Ecosystem model Keystone species List of feeding behaviours Metabolic theory of ecology Productivity Resource Producers Autotrophs Chemosynthesis Chemotrophs Foundation species Mixotrophs Myco - heterotrophy Mycotroph Organotrophs Photoheterotrophs Photosynthesis Photosynthetic efficiency Phototrophs Primary nutritional groups Primary production Consumers Apex predator Bacterivore Carnivores Chemoorganotroph Foraging Generalist and specialist species Intraguild predation Herbivores Heterotroph Heterotrophic nutrition Insectivore Mesopredators Mesopredator release hypothesis Omnivores Optimal foraging theory Predation Prey switching Decomposers Chemoorganoheterotrophy Decomposition Detritivores Detritus Microorganisms Archaea Bacteriophage Environmental microbiology Lithoautotroph Lithotrophy Microbial cooperation Microbial ecology Microbial food web Microbial intelligence Microbial loop Microbial mat Microbial metabolism Phage ecology Food webs Biomagnification Ecological efficiency Ecological pyramid Energy flow Food chain Trophic level Example webs Cold seeps Hydrothermal vents Intertidal Kelp forests Lakes North Pacific Subtropical Gyre Rivers San Francisco Estuary Soil Tide pool Processes Ascendency Bioaccumulation Cascade effect Climax community Competitive exclusion principle Consumer - 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Question: what percentage of sunlight is captured by plants to convert it into food energy