Question

Determine the valency of 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 metal:

1. Consider a Sodium metal atom $\mathbf{\left(}\mathbf{Na}\mathbf{\right)}$ having atomic number $11$. Thus, the number of electrons in a Sodium atom are $11$.
2. The electronic configuration of Sodium is $(2,8,1)$. The outermost shell has $1$ electron.
3. Thus, the number of valence electrons in Sodium is $1$.

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 metal:

1. Metals tend to lose electrons to acquire eight electrons in their outermost shell.
2. They have less than 4 electrons in their valence shell.
3. The valency of the metal is equal to the number of valence electrons.

Example:

1. Sodium metal atom has $1$ valence electron.
2. Thus, it loses $1$ valence electron to acquire eight electrons in its outermost shell.
3. Thus, the valency of Sodium is $1$.