Question

Why are valence electrons important?

Answer 1

They give us the reactivity of the elements.

Explanation:

If the valence electrons of elements are really close or really far to `8`, like `1` or `7`, those elements tend to be very reactive, and don't generally have a lot of oxidation states.

The alkali metals (group `1` elements) each have `1` valence electrons, so they tend to be very reactive, and readily lose that electron.

The halogens (group `7` or `17` elements) each have `7` valence electrons, and will react with almost anything just to get that extra electron to complete its octet.

Have a look at the elements on the periodic table:

Can you predict on which elements are going to be reactive?