Final answer:
Protons and neutrons are heavy particles, while electrons are light particles.
Step-by-step explanation:
The subatomic particles that are considered 'heavy' are protons and neutrons, while electrons are considered 'light'.
A proton has a mass of 1.0073 amu and a charge of 1+. A neutron is slightly heavier with a mass of 1.0087 amu and has no charge. On the other hand, an electron is much lighter with a mass of about 0.00055 amu and has a charge of 1-.
Protons and neutrons are roughly equal in mass, while electrons have a significantly smaller mass compared to both protons and neutrons.