An oxygen atom has a total of 8 elections. How do you write the 4 quantum numbers for each of the 8 electrons in the ground state ?

You know that a neutral oxygen atom has 8 electrons.

It's always helpful to write the for an element before trying to assign for each individual electron . As you can see in the image above, the for neutral oxygen is

##"O": 1s^(2) 2s^(2) 2p^(4)##

Assuming you know the basics behind , you can write the unique 4-number set for each electron belonging to oxygen like this

The first energy level:

##"n=1"##, ##"l=0"##, ##"m"_l"=0"##, ##"m"_s"=-1/2"## ##->## the electron located in the 1s-orbital, spin-down; ##"n=1"##, ##"l=0"##, ##"m"_l"=0"##, ##"m"_s"=+1/2"## ##->## the electron located in the 1s-orbital, spin-up;

The second energy level:

##"n=2"##, ##"l=0"##, ##"m"_l"=0"##, ##"m"_s"=-1/2"## ##->## the electron lcoated in the 2s-orbital, spin-down; ##"n=2"##, ##"l=0"##, ##"m"_l"=0"##, ##"m"_s"=+1/2"## ##->## the electron located in the 2s-orbital, spind-up;

##"n=2"##, ##"l=1"##, ##"m"_l"=-1"##, ##"m"_s"=-1/2"## ##->## the electron located in the ##"2p"_x"-orbital"##, spin-down; ##"n=2"##, ##"l=1"##, ##"m"_l"=-1"##, ##"m"_s"=+1/2"## ##->## the electron located in the ##"2p"_x"-orbital"##, spin-up; ##"n=2"##, ##"l=1"##, ##"m"_l"=0"##, ##"m"_s"=+1/2"## ##->## the electron located in the ##"2p"_y"-orbital"##, spin-up; ##"n=2"##, ##"l=1"##, ##"m"_l"=1"##, ##"m"_s"=+1/2"## ##->## the electron located in the ##"2p"_z"-orbital"##, spin-up;