Which of the following particles are termed nucleons in a neutral atom?

Step 1: Analyze the question The question asks which particles are called nucleons. The word "nucleon" comes from "nucleus", so we are looking for the particles found inside the nucleus.

Step 2: Explain the concept An atom has two main regions:

• Nucleus (centre): contains protons (positive charge) and neutrons (no charge).
• Electron shells (outside the nucleus): contain electrons (negative charge).

Nucleons are the particles that make up the nucleus. Therefore:

Nucleons = protons + neutrons

The nucleon number (also called the mass number, A) is the total number of protons and neutrons in an atom.

Step 3: Check each option

• A. Protons and neutrons: both are in the nucleus, so this is correct.
• B. Neutrons and electrons: electrons are outside the nucleus, so this is wrong.
• C. Protons and electrons: electrons are not nucleons, so this is wrong.
• D. Protons, electrons and neutrons: this includes electrons, so this is wrong.

Step 4: Answer The correct option is A. protons and neutrons.

Tip: Think "NUCLE-ons live in the NUCLE-us." Electrons are never nucleons. Also remember that the nucleon number = protons + neutrons, while the atomic (proton) number = protons only.