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-
OH-
CO3 2-
PO3- 4

Complete the fourth row of the table.

2 answers

As you can see you can't show spaces. Is this what you mean?
K^+......NH4^+......Mg^2+ ......Fe^3+

KCl.....NH4Cl......MgCl2.......FeCl3
KOH.....NH3(aq)....Mg(OH)2.....Fe(OH)3
etc. This is how you do it. What is it you don't understand?
What would the last two be?