Question

What is the electron configuration of `Ni^(+3)`?

Answer 1

I guess it should be `[Ar]3d^7`.

Explanation:

Well, we first need to find a neutral nickel atom's electron configuration.

It is `[Ar]3d^8\4s^2`.

Source: https://en.wikipedia.org/wiki/Nickel

Now, we need to find the electron configuration for a nickel(III) cation.

That means, it has lost three electrons from its electron configuration, and therefore loses both of its `4s` electrons, and one `3d` electron, thus leaving a configuration of

`[Ar]3d^7`.

I hope this helps!