In a redox reaction, why does an element’s oxidation number increase? a.) an element’s oxidation number increases because it gained electrons. b.) an element’s oxidation number increases because it lost electrons. c.) an element’s oxidation number increases because it was heated. d.) an element’s oxidation number increases because it was reduced.

B) An element’s oxidation number increases because it lost electrons.

Explanation:

A redox reaction is a chemical reaction in which one or more electrons are transferred between the reactants, causing a change in their oxidation states.

The oxidation state or oxidation number is defined as the sum of positive and negative charges of an atom, which indirectly indicates the number of electrons that the atom has accepted or yielded.

By accepting electrons, the oxidation state of an atom decreases, becoming more negative, and therefore, it is reduced. On the other hand, an element that yields electrons increases its oxidation number and oxidizes.

In this way, an element’s oxidation number increase because it lost electrons, becoming a more positive ion.