In a typical oxidation reaction as defined in redox chemistry, what happens to the electrons of the species that is being oxidised?

Introduction / Context:
Oxidation and reduction are key ideas in both chemistry and biology. They occur in reactions ranging from corrosion and combustion to cellular respiration and industrial processes. Modern definitions of oxidation and reduction are based on electron transfer. This question asks what happens to the electrons of the species that is undergoing oxidation in a redox reaction.

Given Data / Assumptions:

• A redox reaction involves two half reactions, one oxidation and one reduction.
• Oxidation and reduction can be defined in several ways, including in terms of electron transfer.
• We use the modern electron based definition here.
• Protons and neutrons reside in the nucleus and usually do not change in ordinary redox reactions.

Concept / Approach:
In the electron transfer view, oxidation is defined as the loss of electrons by a species, and reduction is defined as the gain of electrons by a species. You can remember this using the phrase OIL RIG: Oxidation Is Loss, Reduction Is Gain (of electrons). When a metal atom forms a positive ion, it has been oxidised because it gives up electrons. When a non metal or an ion gains electrons, it has been reduced. Protons and neutrons are largely unchanged in typical chemical reactions, which involve only the electron clouds around atoms.

Step-by-Step Solution:
Step 1: Recall the OIL RIG memory aid: Oxidation is loss, reduction is gain of electrons. Step 2: Identify that the question asks specifically about oxidation, not reduction. Step 3: Therefore, the species that is oxidised must be losing electrons during the reaction. Step 4: Check that no mention is made of changes in protons or neutrons in the usual definition of chemical oxidation. Step 5: Choose the option stating that electrons are lost from the species undergoing oxidation.

Verification / Alternative check:
Consider the reaction of sodium with chlorine: 2Na + Cl2 → 2NaCl. In terms of ions, sodium goes from neutral Na to Na+ by giving up one electron per atom, while chlorine goes from Cl2 to chloride ions Cl− by gaining electrons. Here sodium is oxidised because it loses electrons, and chlorine is reduced because it gains electrons. Many other examples, such as the formation of magnesium oxide from magnesium and oxygen, reinforce the same pattern. None of these reactions involve loss of protons or neutrons from the nucleus, which remain constant in chemical changes.

Why Other Options Are Wrong:
- Protons are lost from the nucleus: This would change the element itself and is associated with nuclear reactions, not standard chemical oxidation.
- Neutrons are lost from the nucleus: Again, this describes nuclear processes, not typical oxidation in chemical reactions.
- Electrons are gained by the species: Gaining electrons defines reduction, not oxidation.
- Protons are gained by the species: There is no standard definition of oxidation based on gaining protons in basic chemistry; proton transfer is used in acid base reactions, not in defining redox changes.

Common Pitfalls:
Some students remember older definitions of oxidation such as addition of oxygen or removal of hydrogen and forget that these are special cases, not the most general rule. Others misapply the OIL RIG mnemonic and confuse which process involves loss or gain. Always focus on electrons: oxidation is electron loss, reduction is electron gain. This rule works for all redox reactions and avoids confusion when oxygen or hydrogen is not involved.

Final Answer:
In an oxidation reaction, the oxidised species Electrons are lost from the species.