Answer
Ga will lose 3 electrons.
Li will lose 1 electron.
Br will gain one electron.
S will gain 2 electrons.
Work Step by Step
Since $Galium$ is in group 3 and a metal, it will lose three electrons to obtain a full octet so it becomes $Ga^{3+}$.
Since $Li$ is in group 1 (and a metal), it will lose one electron to obtain a full octet so it becomes $Li^{+}$.
Since $Bromine$ is in group 7 and a non-metal, it will gain one electron to obtain a full octet so it becomes $Br^{-}$.
Since $Sulfur$ is in group 6 and a non-metal, it will gain two electrons to become stable so it becomes $S^{2-}$.
