Created modern periodic table (late 1800’s)

Arranged by increasing atomic number

Similar elements found in columns

Elements are in columns called groups or families

All elements within a group have similar chemical properties

Horizontal rows are called periods

Representative elements are chemically active elements

Transitional metals are in center of the table

Inner transitional metals are the two rows below

s, p, d, and f

Every group on the table ends in the same basic configuration, this gives them their characteristic properties ◦ Group 1 s1

◦ Group 2 s2

◦ Group 3 s2d1

◦ Group 12 s2d10

◦ Group 13 s2d10p1

Period of the element tells the highest main level reached

What is end configuration of each◦ Ca◦ Si◦ Ga