Question

The atom of an element has $20$ protons, $20$ neu­trons, and $20$ electrons. Find out its valency.

Answer 1

Given:

Number of protons$=20$

Number of neutrons$=20$

Number of electrons$=20$

Formula used:

Atomic number$=$Number of protons$=$Number of electrons

Calculate the atomic number:

Atomic number$=$Number of protons$=$Number of electrons

Atomic number$=20$

Thus, the atomic number of the element is $20$.

Write the electronic configuration of Calcium:

1. The total number of electrons in Calcium atom is $20$.
2. Thus, the electronic configuration is $(2,8,8,2)$.

Valency of Calcium:

1. 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.
2. The electronic configuration of Calcium is $(2,8,8,2)$.
3. In order to acquire eight electrons in the outermost shell, Calcium atom loses $2$ electrons from the outermost shell.
4. Thus, the valency of Calcium is $2$.