The nucleus is tiny compared to the atom as a whole:
For comparison, the radius of a methane molecule is 0.5 nm (5 × 10-10 m), the radius of a typical bacterium is 1 × 10-6 m and the radius of a human hair is about 1 × 10-4 m.
The masses of subatomic particles are very tiny. Instead of writing their actual masses in kilograms, we often use their relative masses. The relative mass of a proton is 1, and a particle with a relative mass smaller than 1 has less mass.
|Subatomic particle||Relative mass||Relative charge|
The mass of an electron is very small compared to the mass of a proton or neutron. Since the nucleus contains protons and neutrons, most of the mass of an atom is concentrated in its nucleus.
Protons and electrons have equal and opposite electrical charges.