Question

Determine the valency of non-metal and va­lence electrons with examples.

Answer 1

Valence electrons:

The electrons present in the outermost shell of the atom of an element are known as valence electrons.

Determine the number of valence electrons in a non-metal:

1. Consider a non-metal Fluorine $\mathbf{\left(}\mathbf{F}\mathbf{\right)}$ having atomic number $9$. Thus, Fluorine atom has $9$ electrons.
2. The electronic configuration of Fluorine is $(2,7)$. Thus, there are $7$ electrons in the outermost shell.
3. Thus, the number valence electrons in Fluorine is $7$.

Valency:

The combining capacity of the atom of an element with the atoms of other elements in order to acquire eight electrons (or two electrons in Helium) in its outermost shell is known as valency.

Determine the valency of a non-metal:

1. Non-metals tend to gain electrons to acquire eight electrons in their outermost shell.
2. The valency of the non-metal is $=8-$number of valence electrons.

Example:

1. A non-metal, Fluorine has $7$ valence electrons.
2. Thus, the valency of Fluorine is $=8-7=1$.
3. Thus, Fluorine gains $1$ electron in the outermost shell i.e. its valency is $1$.