Question

What is the oxidation number of the element ge in the compound geo2?

Answer 1

Oxygen has an oxidation state of -2 so considering that there are 2 oxygen atoms,
2 x -2 = -4
The compound is neutrally charged so the sum of all the oxidation states must be zero. Therefore the oxidation state of Ge must be +4 in order to cancel the -4 to make zero.