Question

Na⁺ has completely filled K and L shells. Explain.

Answer 1

We know that the electronic configuration of Na is 2, 8, 1. It has 1 electron in its outer shell. Therefore, it loses one of its electrons, forms Na⁺ and becomes stable. Thus, the K and L shells of Na⁺ are filled.

The atomic number of sodium (Na) = 11

No. of electrons in Na = 11

No. of electrons in Na⁺ = 11 - 1 = 10

Electronic configuration of

Na+	→	2	8
		K	L

For K - shell; 2n² = 2 × 1² = 2

For L - shell; 2n² = 2 × 2² = 8

Thus, in Na+, K and L shells are filled.