Answer
Coordination number: 4
Oxidation number: +2
Work Step by Step
The ligand $(en)_{2}$ that surround the central metal atom $Zn$ are 2, but since $(en)_{2}$ is a bidentate ligand, the coordination number is 4. ($2×2=4$)
Let us suppose the oxidation number of $Zn$ is X. To find the oxidation number, we sum the known oxidation numbers and equal it to the charge on the complex.
Also,
$en_{2} = 2 \times (0)$
$Br_{2} = 2 \times (-1)$
The overall charge is zero on the complex, thus:
$X+2 \times (0) +2 \times (-1)=0$
$X-2 =0$
$X= +2$
The oxidation number of $Zn$ is +2
