Question

Which of the following rules could explain the presence of three unpaired electrons in N-atom?
a) Hund' rule b) Aufbau's principle
c) Heisenberg's uncertainty
d) Pauli's exclusion principle

Answer 1

Answer:

a) Hund's Rule

Explanation:

The presence of three unpaired in Nitrogen can be explained by Hunds rule.

The atomic number of nitrogen is 7

So its electronic configuration will be - 1s2 2s2 2p3

Since the outer most shell is the p shell and P shell has 3 orbitals.

Each of these orbitals can accommodate 2 electrons. But these orbitals are filled according to the Hunds rule which states that pairing can only start after each orbital is singly filled.

Thus each of these 3 electrons occupies one orbital and remain unpaired.