What is the ground state configuration of Cr2+, Cu2 + and Co3+?

The electron configuration for Chromium (II) ion (Cr2+) is: 1s2 2s2 2p6 3s2 3p6 3d4 or [Ar]3d4

The electron confiuration for Copper 2 + (Cu2+) is: Cu2 + = 1s2 2s2 2p6 3s2 3p6 3d9 or [Ar]3d9

The electron configuration for Cobalt 3 + (Co3+) is: 1s2, 2s2, 2p6, 3s2, 3p6, 4s1, 3d5.