Question

Write electron configurations for each of the following. the cations: Mg2+,Sn2+,K+,Al3+,Tl+,As3+

Answer 1

Answer:

• Mg⁺² ⇒ 1s² 2s² 2p⁶

• Sn²⁺ ⇒ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰

• K⁺ ⇒ 1s² 2s² 2p⁶ 3s² 3p⁶

• Al³⁺ ⇒ 1s² 2s² 2p⁶

• Ti⁺ ⇒ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 4f¹⁴ 6s² 5d¹⁰

• As⁺³ ⇒ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

Explanation:

The electron configuration indicates the way the electrons of an atom or ion are structured. In the case of cations, by knowing the electronic configuration of the atom (which is neutral), we can find out the cations' configuration by substracting n outermost electrons, where n is the charge of the cation.

Mg⁰ ⇒ [Ne] 3s² = 1s² 2s² 2p⁶ 3s². Thus

Mg⁺² ⇒ [Ne] = 1s² 2s² 2p⁶.

In a similar fashion, the answers are:

Sn²⁺ ⇒ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰

K⁺ ⇒ 1s² 2s² 2p⁶ 3s² 3p⁶

Al³⁺ ⇒ 1s² 2s² 2p⁶

Ti⁺ ⇒ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 4f¹⁴ 6s² 5d¹⁰

As⁺³ ⇒ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²