When oxidation occurs in an atom its oxidation number increases that is it become positive charged.
Step-by-step explanation:
Oxidation in an atom means the loss of electrons in a reaction.
The atom from which electron is lost is said to be oxidized.
An atom that is oxidized is termed a reducing agent.
There comes a positive charge on atom. Example:
Na - 1e-⇒Na+
Here the Na will have one positive charge after one electron is lost.
When an atom is oxidized the other atom forming compound is reduced.
Oxidation number of mono atomic ions is equal to the charge present on it.