Zinc phosphide, Zn3P2, is often used as a rat poison. Phosphorus has 5 valence electrons and will gain 3 electrons to become stable.

Zinc (Zn) is a transition metal. Metals lose all their valence electrons to become stable and form + ions.

Phosphorus (P) is a non metal. Non metals gain as many electron needed to make them stable by having 8 valence electrons.

If phosphorus has 5 valence electrons, how many more electrons does it need to become stable?

Then the formula for the phosphide ion is ...

Using criss cross method, we give the number of charges of phosphide ion to Zinc in the compound ( without its negative sign).

What number did Zn give to P using the criss cross method according to the formula of Zn3P2,?

Now choose the correct statement to answer this question:

How many valence electrons does each zinc atom lose?