Question

The number of d-electrons retained in Fe²⁺ (At. no. Fe = 26) ion is ______.

Options

• 3

• 4

• 5

• 6

Answer 1

The number of d-electrons retained in Fe²⁺ (At. no. Fe = 26) ion is 6.

Explanation:

The atomic number of iron (Fe) is 26. So, the electronic configuration of a neutral Fe atom is [Ar] 3d⁶ 4s². In Fe²⁺, 2 electrons are lost, and these are lost first from the 4s orbital. So, the configuration of Fe²⁺ becomes [Ar] 3d⁶. This means 6 d-electrons are retained in the Fe²⁺ ion.