Question

In a redox reaction, why does an element’s oxidation number decrease?

Answer 1

That because that element has received electrons from another element 

hope that helps 

Answer 2

Element’s oxidation number decrease that because that element has received electrons from another element

Explanation:

a reduction in oxidation state is known as a reduction. Such reactions include the formal removal of electrons: a net gain in electrons moving a reduction, and a clear loss of electrons being an oxidation.

An oxidation-reduction (redox) reaction is a type of synthetic reaction that involves a transfer of particles between two species. An oxidation-reduction reaction is any synthetic reaction in which the oxidation number of a molecule, atom, or ion quarters by winning or missing an electron.