Answer: B) An element’s oxidation number increases because it lost electrons.
Explanation:
A redox reaction is a chemical reaction in which <u>one or more electrons are transferred between the reactants</u>, causing a change in their <u>oxidation states</u>.
The oxidation state or oxidation number is defined as the sum of positive and negative charges of an atom, which <u>indirectly indicates the number of electrons that the atom has accepted or yielded.</u>
By <em>accepting electrons</em>, the oxidation state of an atom <em>decreases</em>, becoming more negative, and therefore, it is <em>reduced</em>. On the other hand, an element that <em>yields electrons</em> <em>increases</em> its oxidation number and <em>oxidizes</em>.
<u>In this way, an element’s oxidation number increase because it lost electrons, becoming a more positive ion.</u>