Question

List three atoms or ions that have the same electron configuration as each of the following.a) S^2-b) Al^3+c)P^3-

Answer 1

First, we need to know the atomic number of each element, we look for it at the periodic table:

S is 16

Al is 13

P is 15

So:

If you have S²⁻, that means the S gained 2 electrons.

The neutral atom of S has 16 electrons (because of the atomic number)

So if it gained 2 eletrons, S²⁻ have 18 electrons.

We will do the same for the Al³⁺ and P³⁻:

Al³⁺ means that Al lose 3 electrons.

The neutral atom of Al is 13, if it loses 3 electrons, Al³⁺ have 10 electrons.

The neutral atom of P is 15, if it gains 3 electrons, P³⁻ have 18 electrons.

Now we need to make the electronic distribution of each ion:

S²⁻ - 1s² 2s² 2p⁶ 3s² 3p⁶

Al³⁺ - 1s² 2s² 2p⁶

P³⁻ - 1s² 2s² 2p⁶ 3s² 3p⁶

So: S²⁻ and P³⁻ have the same electron configuration.