1s2 2s2 2p6 3s2 3p6
The Fe2 plus electron configuration is 1s2 2s2 2p6 3s2 3p6 3d6.
The electron configuration of Cu2+ is [Ar]3d94s0.
Cobalt electron configuration is [Ar]3d7.4s2.Cobalt(2+) electron configuration is [Ar]3d7.
Cobalt(II) electron configuration is [Ar]3d7.
Li, Be, O: the first term in the abridged electron configuration is [He]. Ca, K: the first term in the abridged electron configuration is [Ar].
The electron configuration of 1s22s22p3s1 is not the ground state electron configuration of any element. This configuration contains 8 electrons, which in the ground state would be oxygen. The ground state configuration of oxygen is 1s22s22p4.
The electron configuration for a magnesium cation Mg2 plus is 1s2.2s2.2p6.
Neither K2+ nor K2+ exist but even a putative configuration is impossible without knowing what one you mean.
The element with that electron configuration is Iron.
K+And the K ion configuration is 1s2 2s2 2p6 3s2 3p6Noble gases have the configuration up to 3p6Pseudo noble gases have it up to 3d10
1s22s22p63s23p64s1 or [Ar]4s1
Iron has the electron configuration [Ar]3d64s2.