The Nucleus
These are all carbon atoms. We used to think that atoms weren't made up of smaller pieces. The word "atom" actually comes from a Greek word which means "can't be split up".
Now we know that all atoms are actually made of the same 3 tiny particles. They are called protons, electrons and neutrons.
The protons are positive and the electrons are negative. Neutrons are neutral.
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Protons and neutrons are much heavier than electrons and they are
found in the middle of the atom called the nucleus. The electrons are in
orbit around the outside.
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There are about 100 different types of atom, that's why there are about 100 elements. ( An element is a substance that contains only one type of atom). So how are atoms different from each other?
Each element has a different number of protons.
| Element | Hydrogen | Helium | Lithium | Beryllium | Boron | Carbon | Nitrogen | Oxygen |
| Proton number | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
The number of electrons is the same as the number of protons
The number of neutrons is usually about the same as the number of protons though bigger atoms tend to have more neutrons than protons.
Can you figure out what the numbers next to the symbol for each atom mean?