Question

How is an electron's outer electron configuration related to its position in the periodic table?

Answer 1

For main-group elements only, the number of valence electrons is often given by the number of the group or family that the element is in.

Explanation:

Group 1 A (`s^1`) has one valence electron.
Group 2 A (`s^2`) has two valence electrons.
Group 8 A (`s^2p^6`) has eight valance electrons.

While there are exceptions, elements in a vertical column typically have the same electron configuration.