Question

What would be the formula of the compound iron (III) phosphide?

Answer 1

Iron (III) is \[Fe ^{3+}\]

Answer 2

Phosphide is\[P ^{3-}\] since it is in group 5A

Answer 3

When ions make a compound, they combine so that the charges cancel out. Since +3 + (-3) = 0, they combine in a ratio of 1:1.

Answer 4

So, what do you think the formula would be?