Energy Levels, Orbitals, Electrons

When an electron is in a particular energy level, it is more likely to be found in some parts of that level than in others. These parts are called orbitals. Orbitals of equivalent energy are grouped in sublevels. Each orbital can contain a maximum of two electrons. The order of the electron orbital energy levels, starting from least to greatest, is as follows: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p. ... So, if there are open orbitals in the same energy level, the electrons will fill each orbital singly before filling the orbital with two electrons.

the answer is barium and copper bromide