Atom
The smallest piece of an element that still counts as that element. Everything around you is built from atoms.
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Analogy
Atoms are like Lego bricks. A few kinds of brick build a huge number of different models.
In practice
A single drop of water holds billions of billions of atoms.
Practice
Flashcards
- Why is a neutral atom neutral?It has the same number of positive protons and negative electrons.
Questions people ask
How small is an atom?
An atom is about 0.0000000001 metres across, which is far too small to see with a normal microscope. About a million atoms placed side by side would stretch across the width of a human hair. Special machines can still image atoms.
Can atoms be split?
Atoms can be split into protons, neutrons and electrons, but then they are no longer the same element. Splitting a nucleus, called nuclear fission, releases huge amounts of energy. Chemical reactions never split atoms. They only rearrange them into new groups.