Periodic Table

Periodic Law:  when elements arranged by atomic #, there’s periodic pattern of properties

P.T. Development

Dobereiner (early 1800’s) classified elements into triads

Newland (1865) Law of Octaves

elements arranged by atomic mass, patterns repeated every 8 elements     

Meyer and Mendeleev (1869) schemes to classify elements

Mendeleev credited with 1^st P.T. of elements by arranging by atomic mass, predicted elements Ge, Ga

Mosely (1913) determined atomic # was nuclear charge, arranged elements by atomic # (current P.T.)

Parts of P.T.

Periods: horizontal rows

Groups/families: vertical columns

       Alkali metals: 1A

       Alkali earth metals: 2A

       Boron, carbon, nitrogen, oxygen families

       Halogens: 7A

       Noble gasses: 8A/0

Representative Elements: A columns

Metals: left of staircase

Nonmetals: right of staircase

Metalloids: elements adjacent to staircase (B, Si, Ge, As, Sb, Te, At)

Transition metals: B columns, middle of P.T.

Inner transition metals: bottom 2 rows