Question

What is understood by valence electrons?

Answer 1

Valence or valency is the number of electrons available for making a chemical bond, those elctrons are called valence electrons (in another way, the electrons of the outermost shell of an atom are called the valence electron.

Explanation:

For example, a carbon atom has six electrons, the electron configuration of carbon atom is : `1s^2` `2s^2` `2p^2`. Which means carbon has 4 electrons in its outermost shell.
So valence of carbon is 4, and these 4 electrons are valence electrons.