Which of the following is true about subatomic particles?
electrons are negatively charged and are the heaviest subatomic particle.
protons are positively charged and the lightest subatomic particle.
neutrons have no charge and are the lightest subatomic particle.
the mass of a neutron nearly equals the mass of a proton.

Option (d) is the correct answer.

Explanation:

Nucleus of an atom contains three subatomic particles. These are protons, neutrons and electrons.

Mass of a proton is kg.

Mass of a neutron is kg.

Mass of an electron is kg.

Also, protons are positively charged, neutrons have no charge and electrons are negatively charged.

Therefore, we can conclude that the mass of a neutron nearly equals the mass of a proton.