Answer:
Neon is stable, hence has no charge.
Oxide (O2-) has a charge of -2
Cooper (Cu2+) has a charge of +2
Tin (Sn2+) has a charge of +2
hence overall charge = -2+2+2
<em><u>Over</u></em><em><u>all</u></em><em><u> </u></em><em><u>charge</u></em><em><u> </u></em>= +2
You can work out the percentage change and that would help you work out the rate of appreciation :)
The formula is ((new value - old value)/old value) * 100.
So you do 
Therefore the rate of appreciation is 8% p/a.