Answer
See explanation below.
Work Step by Step
a.) Rb forms Rb+ with a +1 charge. [Rb+] = 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
b.) N forms N^3- with a -3 charge. [N^3-] = 1s2 2s2 2p6
c.) Br forms Br- with a -1 charge. [Br-] = 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
