Answer
d. 1s2, 2s2, 2p5
Work Step by Step
Generally carbon has 6 electrons in its ground state
C3- means the carbon has gained 3 electrons
thus now it has a total of 9 electrons giving it its new electronic configuration.
as 2+2+5=9 and s subshells can only hold 2 electrons and p subshells can only hold a maximum of 6 electrons.
