GCSE Physics


An element* is the simplest building block in chemistry. In other words, atoms. However, not all atoms of an element need to be the same.

As long as they have the same number of protons* in the nucleus and electrons* outside, they will behave exactly the same.

Add in extra neutrons, and the atom is heavier. It is still the same element. Take a neutron out, making it lighter, and it's still the same element.

Atoms of a particular element with different numbers of neutrons are called isotopes.

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