Answer:
The oxidation number of tin (Sn) in the compound Na₂SnO₂ is +2 (option C)
Step-by-step explanation:
First of all you should know that the oxidation state of a neutral element or molecule is 0. Then the sum of the oxidation states of the atoms that form a neutral molecule is zero.
On the other hand, the metals of group 1 (alkaline), as in the case of sodium Na, have an oxidation number of +1. And the oxidation state of oxygen in the compounds is -2.
Finally, you must take into account the amount of each element present in the compound, for which you observe the subindice.
Given this, it is possible to express:
2*oxidation number of sodium+1*oxidation number of tin+2*oxidation number of oxigen=0
2*(+1)+1*oxidation number of tin+2*(-2)=0
2+oxidation number of tin-4=0
-2+oxidation number of tin=0
oxidation number of tin=2
The oxidation number of tin (Sn) in the compound Na₂SnO₂ is +2 (option C)