In: Chemistry
Oxidation is chemical reaction where a loss of electron occur, it is also define as the addition of oxygen, removal of hydrogen, increase in oxidation state etc. Thus, on oxidation Cu would lose its electron to form Cu2+ ions.
Example for oxidation reactions are as follows:
Na -----------> Na+ + e
C + O2 -----------> CO2
Now, coming back to your questions, copper does not oxidise on heating, on heating copper absorbs sufficient energy and becomes activated for a reactions. However, if heated in an open system where air is present then copper reacts with oxygen present in it for form a black solid of copper oxide.
The balanced chemical equation for the reactions is as follows:
2Cu + O2 -----------> 2CuO
Please note if copper heated in absence of oxygen then no oxidation of copper would occur.