POSSIE Gallium (Ga) is a soft, silvery metal used primarily in electronic circuits, semiconductors, and light-emitting diodes (LEDs). It is also useful in high-temperature thermometers, barometers, pharmaceuticals, and nuclear medicine tests. Which electron configuration represents the electrons in an atom of gallium at ground state? O1s 2s22p63s23p64524d104p? O 182 2s22p63s23p64s24p1 o 1s 2s22p63s23p64823d104p? O 182 2s22p63s23p64s3

The ground state configuration : 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p¹

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