Question #f444a

1 Answer
May 12, 2017

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