Name ____________________________________ Period ____________ 6-1 Development of the Periodic Table The early periodic table 30 By the end of the 1700’s scientists had identified only elements 65 line By the mid 1800’s about elements had been identified using spectra photography and spectra chemical physical where so many individual elements with slightly different and properties that it became hard to keep track of all of them. organization system Chemists began to need a to help keep tack of all these similar but slightly different elements This organization system would ideally group the elements in a way that described there chemical physical properties and Dmitri Mendeleev and the first periodic table 1st periodic table Dmitri Mendeleev Organized the according to increasing – atomic mass chemical physical Mendeleev put elements with similar and properties vertical column. in the same a vertical column of elements on Mendeleev periodic table that have similar chemical and Group- properties physical Mendeleev noticed that when elements where arranged according to atomic mass some elements don’t fit into the predicted group. Because of this Mendeleev arranged some elements out of order and put them in the group that best matched their chemical properties. three empty spaces He also left in his table and used his groups to correctly 3 unidentified elements. predicted the properties of these Moseley and the periodic law number Moseley reorganized Mendeleev’s periodic table the periodic table by atomic instead of mass atomic When the periodic table was reorganized in this way it was found that all the elements fell into the correct group without the need to reorganize increasing atomic The Periodic Law - When elements are arranged in order of number, predictable their physical and chemical properties show a pattern. 6-2 Reading the Periodic Table What is the periodic table of the elements? The periodic table of the elements is a chart that lists all the elements that have ever existed in a meaningful way. The elements square on the table contains information unique to that element like atomic number, atomic symbol, name of the element and average atomic mass of the element
Name ____________________________________ Period ____________ 6-1 Development of the Periodic Table The early periodic table By the end of the 1700’s scientists had identified only 30 elements By the mid 1800’s about 65 elements had been identified using spectra photography and line spectra where so many individual elements with slightly different chemical and physical properties that it became hard to keep track of all of them. Chemists began to need a organization system to help keep tack of all these similar but slightly different elements This organization system would ideally group the elements in a way that described there chemical and physical properties Dmitri Mendeleev and the first periodic table Dmitri Mendeleev – Organized the 1st periodic table according to increasing atomic mass Mendeleev put elements with similar chemical and physical properties in the same vertical column. Group- a vertical column of elements on Mendeleev periodic table that have similar chemical and physical properties Mendeleev noticed that when elements where arranged according to atomic mass some elements don’t fit into the predicted group. Because of this Mendeleev arranged some elements out of order and put them in the group that best matched their chemical properties. He also left three empty spaces in his table and used his groups to correctly predicted the properties of these 3 unidentified elements. Moseley and the periodic law Moseley reorganized Mendeleev’s periodic table the periodic table by atomic number instead of atomic mass When the periodic table was reorganized in this way it was found that all the elements fell into the correct group without the need to reorganize The Periodic Law - When elements are arranged in order of increasing atomic number, their physical and chemical properties show a predictable pattern. 6-2 Reading the Periodic Table What is the periodic table of the elements? The periodic table of the elements is a chart that lists all the elements that have ever existed in a meaningful way. The elements square on the table contains information unique to that element like atomic number, atomic symbol, name of the element and average atomic mass of the element
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