Question

How many valence electrons are in an atom of phosphorus?

Answer 1

Valence electrons:-

• The electrons which are distributed in the outermost shell of the atom are called valence electrons.
• These valence electrons can form a chemical bond only if the outer shell remains unclosed.

Valence electrons in a Phosphorus atom:-

• Phosphorus belongs to the pnictogen family(group 15) and third period.
• The atomic number of Phosphorus is 15.
• The electronic configuration can be written as $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^3$
• The valence electrons is the sum of the electrons in the outermost shell, that is two $3\mathrm{s}$ electrons and three $3\mathrm{p}$ electrons which gives a total of five valence electrons.

Therefore, the valence electron in a Phosphorus atom is 5.