Question

What is the formula for iron(II) oxide?

Answer 1

FeO

Explanation:

Iron II has a positive 2 charge.
s has a negative 2 charge
They combine in 1:1 ratio
The formula is therefore Fe O

Answer 2

The formula for iron(II) oxide is `"FeO"`.

Explanation:

The formula for the iron(II) ion is `"Fe"^(2+)"` and the formula for the oxide ion is `"O"^(2-)"`. An ionic compound is neutral, so the positive and negative charges are equal. In the case of iron(II) oxide, one `"Fe"^(2+)"` ion combined with one `"O"^(2-)"` ion creates a neutral compound. `2^+ + 2^(-) = 0`