The Periodic Table & Atomic Structure The periodic table is an arrangement of the known elements. The modern periodic table has the elements arranged in order of increasing atomic number…….the early versions had the elements arranged according to atomic mass. Can you find examples where this would be different to the modern version? The periodic table briefly Independently arrived at by Mendeleev and Meyer in the mid-19th century. Mendeleev predicted the properties of undiscovered elements and left spaces in his periodic table. Consists of a series of horizontal rows, periods and vertical columns, groups: Group 1: Alkali metals Group 2: Alkaline earth metals Group 7: Halogens Group 8: Inert gases provides a summary of atomic weights and numbers, symbols and names for the elements understanding of properties of related elements Chemical Formulae A chemical symbol represents one atom of an element. A chemical formula represents one molecule or one formula unit of an element or compound The formula shows: Each type of atom present The number of each atom present in the molecule or formula unit Coefficients, superscripts and subscripts where necessary A molecule is a group of atoms which are bonded together…the atoms may be the same or different. Examples: Elements Compounds H2 = hydrogen H2O = water P4 = phosphorus C6H12O6 = glucose O2 = oxygen NH3 = ammonia A formula unit represents the simplest ratio of atoms in a substance, which may be a giant lattice
The Periodic Table & Atomic Structure The periodic table is an arrangement of the known elements. The modern periodic table has the elements arranged in order of increasing atomic number…….the early versions had the elements arranged according to atomic mass. Can you find examples where this would be different to the modern version? The periodic table briefly Independently arrived at by Mendeleev and Meyer in the mid-19th century. Mendeleev predicted the properties of undiscovered elements and left spaces in his periodic table. Consists of a series of horizontal rows, periods and vertical columns, groups: Group 1: Alkali metals Group 2: Alkaline earth metals Group 7: Halogens Group 8: Inert gases provides a summary of atomic weights and numbers, symbols and names for the elements understanding of properties of related elements Chemical Formulae A chemical symbol represents one atom of an element. A chemical formula represents one molecule or one formula unit of an element or compound The formula shows: Each type of atom present The number of each atom present in the molecule or formula unit Coefficients, superscripts and subscripts where necessary A molecule is a group of atoms which are bonded together…the atoms may be the same or different. Examples: Elements Compounds H2 = hydrogen H2O = water P4 = phosphorus C6H12O6 = glucose O2 = oxygen NH3 = ammonia A formula unit represents the simplest ratio of atoms in a substance, which may be a giant lattice