The Periodic Table

Describing the Periodic Table Elements are only made up of one type of atom. Groups/Families –18 vertical columns, each column is numbered –Elements in each column have similar properties (NOT identical) Periods –7 horizontal rows –Not alike in properties

The Periodic Table Column = Group or Family 18 columns on the Periodic Table Row = Period 7 rows on the Periodic Table

Metals, Nonmetals, and Semi-metals Metals are to the left of the stair- step Only nonmetal on the metal side Nonmetals are on the right of the stair-step Semi-metals, “metalloids,” touch the stair-step

Describing the Periodic Table

Periodic Table Block Atomic Numbers – the top number in the element’s block (whole number) –Tells the number of protons in the nucleus –In a neutral atom, also tells the number of electron. –Atomic number = protons = electrons

Block Atomic Mass- the number found below the element symbol (usually a decimal) –the number of protons plus neutrons increases up the table. –The weighted average mass of an atom of an element –The unit used for atomic mass is atomic mass unit (amu)

Periodic Table Block Atomic Symbol: The atomic symbol is one or two letters chosen to represent an element ("H" for "hydrogen," etc.). Usually, a symbol is the abbreviation of the element or the abbreviated Latin name of the element.

What does the information in the box tell me? 1 H Atomic Number = # of protons Atomic Mass = # of protons plus neutrons Elemental Symbol