Chapter 1 of 10All chapters
Chapter 1 of 10
Atoms
Protons, neutrons and electrons.
The parts
A nucleus of protons and neutrons sits at the centre, with electrons around it. Protons carry positive charge, electrons negative, and neutrons none.
- The proton count is the element and never changes in chemistry.
- Different neutron counts are isotopes; different electron counts are ions.
Mostly empty
If a nucleus were a marble, the nearest electrons would be hundreds of metres away. Solidity comes from electrical repulsion between electron shells, not from matter filling space.