Question

Find out the valency and electrovalency shown by the: Magnesium atom

Answer 1

Valency:

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

Valency of Magnesium $\mathbf{\left(}\mathbf{Mg}\mathbf{\right)}$:

1. Magnesium atom $\mathbf{\left(}\mathbf{Mg}\mathbf{\right)}$ having atomic number $12$. Thus, the number of electrons in a Magnesium atom are $12$.
2. The electronic configuration of Magnesium is $(2,8,2)$.
3. In order to acquire eight electrons in the outermost shell, Magnesium atom loses $2$ electrons from the outermost shell.
4. Thus, the valency of Magnesium is $2$.

Electrovalency:

When an element combines with another element by losing and gaining electrons to form a compound, its valency is called electrovalency.

Electrovalency of Magnesium $\mathbf{\left(}\mathbf{Mg}\mathbf{\right)}$:

1. Magnesium atom $\mathbf{\left(}\mathbf{Mg}\mathbf{\right)}$ has atomic number $12$. Thus, the number of electrons in a Magnesium atom are $12$.
2. The electronic configuration of Magnesium is $(2,8,2)$.
3. In order to acquire eight electrons in the outermost shell i.e. to attain nearest noble gas configuration, Magnesium atom loses $2$ electron from the outermost shell.
4. This leads to formation of Magnesium ion having two units of positive charges $\mathbf{\left(}{\mathbf{Mg}}^{\mathbf{2}\mathbf{+}}\mathbf{\right)}$.
5. Thus, the electrovalency of Magnesium is $+2$.