Question

Candium forms the ion Sc3+. How many bromite ions could bond with Sc3+, and what would be the chemical formula?

Answer 1

Answer: 3 bromite ions and $Sc(BrO_2)_3$

Explanation:

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.  

Here scandium is having an oxidation state of +3 called as $Sc^{3+}$ cation and bromite is an anion with oxidation state of -1 called as $BrO_2^-$. Thus 1 Scandium ion combines with three bromite ions and their oxidation states are exchanged and written in simplest whole number ratios to give neutral $Sc(BrO_2)_3$