Final answer:
Oxidation is the loss of electrons, resulting in an atom becoming a cation with more protons than electrons. This process also involves the gain of oxygen or loss of hydrogen in a chemical reaction.
Step-by-step explanation:
Oxidation is defined as the loss of one or more electrons in a chemical reaction. When a substance loses electrons, it is said to be oxidized. This process can also be viewed as the gain of oxygen or the loss of hydrogen. Conversely, reduction involves the gain of electrons or loss of oxygen. The term OIL RIG is often used to remember this principle, which stands for "Oxidation Is Loss, Reduction Is Gain" of electrons.
In the context of ions, when an atom loses electrons, it becomes a positively charged ion known as a cation. For example, when a sodium atom loses one electron, it becomes a sodium cation with a +1 charge due to there being more protons than electrons. This loss of negatively-charged electrons corresponds to an increase in the oxidation number of the element or ion involved in the oxidation process.