Chapter 3, Problem 99E

For each of the following pairs of ions, write the symbol for the formula of the compound they will form.

(a) Ca²⁺ , ${\text{S}}^{\text{2-}}$

(b) ${\text{NH}}_{\text{4}}{}^{\text{+}}\text{,}$

${\text{SO}}_{\text{4}}{}^{\text{2-}}$

(c) ${\text{Al}}^{\text{3+}}\text{,}$

${\text{Br}}^{\text{-}}$

(d) ${\text{Na}}^{\text{+}}\text{,}$

${\text{HPO}}_{\text{4}}{}^{\text{2-}}$

(e) ${\text{Mg2}}^{\text{+}}\text{,}$

${\text{PO}}_{\text{4}}{}^{\text{3-}}$