MCQ Detailed View

Atoms are made of three fundamental subatomic particles: electrons, protons, and neutrons. Each particle has a different mass, which determines its contribution to the total mass of the atom. The heaviest particle among these is the neutron.

The mass of an electron is extremely small, about 9.11×10−319.11 \times 10^{-31}9.11×10−31 kg. It is approximately 1836 times lighter than a proton or neutron. Electrons revolve around the nucleus and contribute almost nothing to the total mass of an atom.

Protons have a mass of approximately 1.67×10−271.67 \times 10^{-27}1.67×10−27 kg. They are located inside the nucleus and are positively charged. Protons define the atomic number of an element and contribute significantly to the atom’s mass.

Neutrons have a mass slightly greater than that of protons, around 1.675×10−271.675 \times 10^{-27}1.675×10−27 kg. This makes neutrons the heaviest subatomic particle among the given options. Although the difference in mass between a proton and a neutron is very small, neutrons are slightly heavier because they do not have a positive charge and contain a small amount of additional binding energy from the strong nuclear force.

All three particles have mass, but the majority of an atom’s mass comes from protons and neutrons inside the nucleus. Neutrons are essential for the stability of the nucleus. Without neutrons, the repulsive forces between protons would make the nucleus unstable. Different numbers of neutrons in an atom create isotopes of the same element.

The knowledge of subatomic particle masses is important in nuclear chemistry, atomic physics, and the calculation of atomic mass units (amu). Among the particles listed, the neutron is the heaviest, followed by the proton, while the electron is the lightest by a very large margin.