Question

How many unshared pair of electrons does an ammonia molecule have?

(a) 1

(b) 2

(c) 3

(d) 4

This question was posed to me in an internship interview.

My doubt stems from P-Block Elements topic in portion P-Block Elements of Chemistry – Class 12

Answer 1

The correct choice is (a) 1

For explanation I would say: The nitrogen atom in NH3 (ammonia) bears one lone pair of electron. Each single electron of hydrogen is bonded to the nitrogen atom. Three of out five electrons of nitrogen are involved in bonding whereas the unbounded two electrons make up the single unshared pair of electron.