The atom as a stadium
If an atom were a stadium, the nucleus of protons and neutrons would be a marble at the centre and the electrons would be gnats buzzing in the far stands — almost all of it empty space. That tiny core still holds nearly all the atom's mass.
What atoms are made of
- Protons — positive charge, in the nucleus
- Neutrons — no charge, in the nucleus
- Electrons — negative charge, orbiting the nucleus
Atomic number
An element's atomic number equals its number of protons. Carbon has 6 protons, so its atomic number is 6.