Question

What are the symbol formulae of barium oxide, rubidium nitride, and magnesium chloride?

Answer 1

Consider the position of each metal ion on the Periodic Table. An ionic compound requires that the charge of each ion sums to neutral.

Explanation:

And then consider the position of the gegenion, to get the charge of the non-metal.

`A.` `"Barium and oxygen"`; barium is in Group 2, and tends to form `Ba^(2+)` ions. Oxygen is in Group 16, and tends to form `O^(2-)` ions as its oxide. `BaO` is the likely formula.

`B.` `"Rubidium and nitrogen"`; barium is in Group 1, and exclusively forms `Rb^(+)` ions. Nitrogen is in Group 15, and tends to form `N^(3-)` ions as its nitride. `Rb_3N` is the likely formula.

`C.` `"Magnesium and chlorine"`; magnesium is in Group 2, and tends to form......... Chlorine is in Group 17.............You tell me the formula?