Question

An element X of group 15 exists as a diatomic molecule and combines with hydrogen at 773 K in presence of the catalyst to form a compound, ammonia which has a characteristic pungent smell.

Identify the element X. How many valence electrons does it have?

Answer 1

Identification of element X and the number of electrons in the valence shell.

• It is given that the element X forms Ammonia $\left({\mathrm{NH}}_3\right)$.
• Ammonia is ${\mathrm{NH}}_3$. It contains two elements i.e.; Nitrogen $\left(\mathrm{N}\right)$ and Hydrogen $\left(\mathrm{H}\right)$.
• Hydrogen is a group- $1$ element whereas nitrogen is group-$15$ element.
• It is given that X is a group-$15$ element, therefore it can be concluded that element X is Nitrogen.

The atomic number of Nitrogen =$7$

• The electronic configuration of Nitrogen is $2,5$.
• So the number of electrons in the valence shell is $5$.