ch. 3 - compound names & formulas quiz\nstarted: sep 16 at 7:12pm\nquiz instructions\ngood luck.\nquestion…

Explanation:

Step1: Determine ion charges

Magnesium (Mg) is in Group 2 of the periodic - table and has a +2 charge ($Mg^{2 + }$), chlorine (Cl) is in Group 17 and has a -1 charge ($Cl^{-}$).

Step2: Balance charges

To balance the charges in an ionic compound, we need 2 chloride ions ($Cl^{-}$) for every magnesium ion ($Mg^{2+}$). So the formula is $MgCl_{2}$.

Answer:

C. $MgCl_{2}$