Answer
a) $CaBr_{2}$
b) $CuI$
c) $FeBr_{3}$
d) $MgS$
e) $CrCl_{2}$
f) $Na_{2}O$
Work Step by Step
If valency of an element A is 'x' and valency of another element B is 'y' then the formula of the compound is $A_{y}B_{x}$.
If valency of an element A is 'x' and valency of another element B is also 'x' then the formula of the compound is $AB$.
If valency of an element A is 'x' and valency of another element B is 'nx' then the formula of the compound is $A_{n}B$.
