Cobalt is an element, there is no oxygen.
The oxygen atom is neutral.
While containing four electrons, carbon can also have a positive or negative charge. The charge can be either +4 or -4.
Zero
Oxygen -2 Hydrogen +1
Oxygen needs 8 electrons to have no charge.
ALL atoms whatsoever DO NOT have a charge!! They're neutral.
The resulting oxygen ion has a charge of -2.
ketone bears negative charge on the oxygen atom of the carbonyl group.
During oxidation an oxygen atom gain two electrons.
atom
atom
No. On its own oxygen is neutral. Its ion, the oxide ion, has a negative charge