Question

Write electron configurations for each of the following.

a. the cations: Mg²⁺, Sn²⁺, K⁺, Al³⁺, Tl⁺, As³⁺

b. the anions: N^3-, O^2-, F^-, Te^2-

Short answer

Cations

1. Mg²⁺ - 1s² 2s² 2p⁶
2. Sn²⁺ - 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰
3. K⁺ - 1s² 2s² 2p⁶ 3s² 3p⁶
4. Al³⁺ - 1s² 2s² 2p⁶
5. Ti³⁺ - 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²
6. As³⁺ - 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰

Anions

1. N^3- - 1s² 2s² 2p⁵
2. O^2- - 1s² 2s² 2p⁶
3. F^- - 1s² 2s² 2p⁶
4. Te^- - 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶

Step-by-step solution

Describing the electron configuration

The electron configuration is the order of electrons assigned in the subsequent subshells of an atom according to their subshell energy and positionin an atom.

Describing the order

Electrons should be arranged according to their subshells energy in the increasing order is as follows:-

1s< 2s< 2p< 3s< 3p< 4s< 3d< 4p< 5s< 4d< 5p< 6s< 4f< 5d< 6p< 7s< 5f< 6d< 7p< 8s< 5g< 6f< 7d< 8p.