Question

Give two examples for:
1. A polyatomic ion with charge of -2

2. An element of group 1

3. An element having valence +3

4. A divalent element​

Answer 1

Answer:

1) 02^2- peroxide or SO4^2- (most appropriate)

2) H, Li, Na, K, Rb, Cs, Fr

3) Al

4) O^2-