The world around you is made up of elements and compounds, atoms and molecules. But what are these things?

The model of a lithium atom
Atoms
- Atoms are tiny particles which make up elements
- Atoms are particles which cannot be divided further
- There are currently 118 different elements
- Atoms of one element are different to atoms of every other type of element
Molecules
- Are made up of two or more atoms chemically bonded (joined) together
- It is not possible to separate the atoms in a molecule without breaking bonds
Elements
- Elements are made up of just one type of atom
- For example Oxygen, O2, is a molecule made up of Oxygen atoms only and is therefore an element.
- The periodic table contains all 118 known elements
Compounds
- Compounds are molecules made up of more than one type of atom chemically bonded together.
- For example Water, H2O, which contains 2 Hydrogen atoms and 1 oxygen atom bonded to each other

Structure of a water molecule, a compound containing 1 Oxygen atom bonded to 2 Hydrogen atoms
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