Protons and electrons are called fundamental particles because they----------

Analyze the question We need to find why protons and electrons are called "fundamental particles" of an atom. In chemistry at WASSCE level, fundamental (subatomic) particles are the basic building blocks that make up atoms: protons, neutrons and electrons.

Explain the concept Fundamental particles of the atom are the particles common to the atoms of all elements. Every atom (apart from ordinary hydrogen, which has no neutron) is built from protons, neutrons and electrons. So they are "fundamental" because they are the basic constituents present in all matter.

Check each option

• A. are indivisible: At the WASSCE level this is not the reason. Protons are in fact made up of quarks, so this is not strictly true.
• B. have different charges: This describes a property, not why they are called fundamental. Neutrons are also fundamental but have no charge.
• C. are the lightest particles: Not true. A proton is about 1836 times heavier than an electron, so a proton is not "the lightest".
• D. are found in all matter: Correct. All atoms contain them, and since all matter is made of atoms, these particles are the basic building blocks of all matter.

Answer The correct option is D.

Tip When you see "fundamental particles", think "basic building blocks present in every atom". Be careful with "indivisible", as it is a tempting distractor, since modern physics shows protons can be divided into quarks.