Complete the table by filling in the formula for the ionic compound formed by each pair of cations and anions, as shown for the first pair. ion k+ nh+4 mg2+ fe3+ cl− kcl oh− co2−3 po3−4

In chemistry, the elements that exist with electrical charges are called ions. These ions can carry a positive charge, for which they are called cations, or a negative charge, for which they are called anions. These ions carry an electric charge because they do not conform to the stable number of electrons of their neutral atom. Because of this, they carry excess electrons for cations, and a lack of electrons for the anions.

When cations and anions form together such that there is a complete transfer of electrons so that each ion would be neutral, an ionic bond is formed. If you write the reaction, the superscripts and subscripts would just cross-multiply. If the cation is A⁺ᵃ, and the anion is B⁻ˣ, then the ionic compound would then be AₓBₐ. Of x=a, then they will cancel out which will yield AB. Therefore, the ionic compound for each pair of ions are:

NH₄⁺ + OH⁻ = NH₄OH
Mg²⁺ + CO₃²⁻ = MgCO₃
Fe³⁺ + PO₃⁴⁻ = Fe₄(PO₃)₃