The word equation for the formation of copper oxide depends on which specific copper oxide you are referring to. There are two common ones:

1. Copper(I) oxide (Cu₂O):

* Copper + Oxygen → Copper(I) oxide

2. Copper(II) oxide (CuO):

* Copper + Oxygen → Copper(II) oxide

Both of these reactions require heat to occur.

It's important to remember that the word equation is just a simplified way to represent a chemical reaction. The actual chemical equation would include the chemical formulas and balancing coefficients:

Copper(I) oxide:

* 2 Cu + O₂ → 2 Cu₂O

Copper(II) oxide:

* 2 Cu + O₂ → 2 CuO