Answer:
1. Category +1: [tex]H^{+1}_{2}O^{-2}[/tex], [tex]H^{+1}Cl^{-1}[/tex], [tex]N^{-3}H^{+1}_{3}[/tex], [tex]Na^{-1}H^{+1}[/tex] ,[tex]C^{-4}H^{+1}_{4}[/tex]
2. Category -1: [tex]Mg^{+2}H^{-1}_{2}[/tex], [tex]Ca^{+2}H^{-1}_{2}[/tex]
3. Category 0: [tex]H^{0}_{2}[/tex]
Explanation:
1. Category +1:
The more common number of oxidation of the oxygen is +1.
[tex]H^{+1}_{2}O^{-2}[/tex]
[tex]H^{+1}Cl^{-1}[/tex]
[tex]N^{-3}H^{+1}_{3}[/tex]
[tex]Na^{-1}H^{+1}[/tex]
[tex]C^{-4}H^{+1}_{4}[/tex]
2. Category -1:
The hydrogen takes the number of oxydation -1 in the hydrides.
[tex]Mg^{+2}H^{-1}_{2}[/tex]
[tex]Ca^{+2}H^{-1}_{2}[/tex]
3. Category 0:
The number of oxydation of an isolated element is always 0.
[tex]H^{0}_{2}[/tex]
