Answer:
Co = 1s2 2s2 2p6 3s2 3p6 4s2 3d7
Explanation:
Number of electrons = 27
The closest noble gas before cobalt is Argon and argon has 18 electrons.
Co = [Ar] ; Remains 27 - 18 = 9 more electrons to fill.
The next orbital in order of increasing energy is the 4s orbital. However it can only hold a maximum of 2 electrons.
We have;
Co = [Ar] 4s2; Remains 27 - 20 = 7 more electrons to fill.
The next orbital in order of increasing energy is the 3d orbital. It can have a maximum of 10 electrons.
So we have;
Co = [Ar] 4s2 3d7
The electronic configuration of Ar = 1s2 2s2 2p6 3s2 3p6
This means the entire configuration of cobalt is;
Co = 1s2 2s2 2p6 3s2 3p6 4s2 3d7
