Answer
(a) $BrO^-$
(b) $SO_4^{2-}$
(c) $IO_3^-$
(d) $NO_2^-$
Work Step by Step
For some of the oxoanions, we may have to refer to the internet for their formulas and charges.
(a) Sodium (Na) has an oxidation number of $1+$ because it has a single electron in its outermost energy level that it can donate to another atom or ion. Hypobromite has a formula of $BrO^-$. Therefore, the compound formed between these two substances is $NaBrO$.
(b) Potassium (K) has an oxidation number of $1+$ because it has a single electron in its outermost energy level that it can donate to another atom or ion. Sulfate has a formula of $SO_4^{2-}$. Therefore, the compound formed between these two substances is $K_2SO_4$.
(c) Lithium (Li) has an oxidation number of $1+$ because it has a single electron in its outermost energy level that it can donate to another atom or ion. Iodate has a formula of $IO_3^-$. Therefore, the compound formed between these two substances is $LiIO_3$.
(d) Magnesium (Mg) has an oxidation number of $2+$ because it has two electrons in its outermost energy level that it can donate to another atom or ion. Nitrite has a formula of $NO_2^-$. Therefore, the compound formed between these two substances is $Mg(NO_2)_2$.
