What is the ground-state electron configuration of a neutral atom of cobalt? express your answer in condensed form, in order of increasing orbital energy. for example, [he]2s22p2 would be entered as [he]2s^22p^2 ?

the atomic number of cobalt is 27

when writing the electronic configuration of cobalt, electrons are arranged into energy shells and subenergy shells .

the complete electron configuration for cobalt is as follows

Co - 1s² 2s² 2p⁶ 3s² 3p⁶  3d⁷ 4s²

we can write this in the condensed form

writing in condensed form is when you write the noble gas symbol for the noble gas with the closest atomic number

Ar is the closest noble gas with atomic number of 18

electron configuration for Ar is as follows

Ar - 1s² 2s² 2p⁶ 3s² 3p⁶

so we can substitute Ar in the electron configuration upto the 18th electron

so the condensed electron configuration for Co is as follows

[Ar] 3d⁷ 4s² 

the answer is either b or c