Question

Question #f444a

Answer 1

No, they cancel out.

Explanation:

Valency is the combining power of an element.

Let's use `Ca^(2+)` and `O^(2-)`

Valency of `Ca^(2+)`= 2
Valency of `O^(2-)`= 2

When they combine, they cancel out into `CaO`.

(Don't put this on the exam, but you can think of the formula looking like `Ca_2O_2` before they cancel out)

Let's use one more example: `K^+` and `O^(2-)`

Valency of `K^+`= 1
Valency of `O^(2-)`= 2

When they combine, we basically switch the valencies so that the 2 goes by the `K` and the 1 goes by the `O`

So `K_2O_1` but the 1 is understood so we don't write that in the final formula which is `K_2O`