How do you write the noble-gas electron configuration for copper?
to write E.C. easily, first thing you need to do is to find the atomic number for an element (ex.Gallium[Ga])
Ga has atomic number of 31.
find a noble gas that is lower than Ga. so Argon(Ar)
Note_All noble gas have complete last electronic config.
 -subtract the atomic number of Gallium to Argon
Atomic number:Ga - Ar/31 -18 = 13
add 13 to the electronic configuration of Argon
(Ar)3d^10 4s^2 4p^1