Question

How do I solve question 18

Answer 1

18. You can cross over the + - number on the top to each other or make them = 0.
a. K2S ........K+ => K 2 from S2.... S2- => S
b. CaO........
c. Na2O
d. AIN

19.
a. BaCl2
b. MgO
c. Li2O
d. CaF2

20.
b. Li, Cl

d. I, Na

Answer 2

To solve number 18 you have to add the positive and negative to equal zero. For example for 18a it would be K2S ( the 2 is a subscript ) because you need 2 positives to cancel out the 2 negatives.