The ground state configuration : 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p¹
Further explanation
Electrons can move the shell up or down by releasing energy or absorbing energy
It can be concluded that there are 2 conditions:
Ground-state is the state of electrons filling the shell with the lowest energy levels.
Excited-state is the state of electrons which occupies a higher energy level
The state of excited electrons can be seen from the presence of electrons which do not fill the shell completely but fill the shell afterward
Gallium (Ga) is a metal located in group 13, p-block and period 4
Atomic number : 31
If we look at the options:
options 1,2 and 3 do not conform to Aufbau principle(Electrons occupy orbitals of the lowest energy level ), because 3d orbitals do not exist and the number of electrons is also not 31
So that the most appropriate electron configuration is:
1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p¹ = 31 electrons
or we can write : [Ar] 4s² 3d¹⁰ 4p¹