Pocket Genius Science: Matter and materials – Atoms

Facts At Your Fingertips: Matter and materials – Atoms

Atoms are the tiny building blocks that make up everything in the universe, including ourselves.

They are far too small to be seen, even with the most powerful microscopes. Billions of them could fit on the dot of this “i.” Yet atoms are themselves made up of even tinier subatomic particles called protons, neutrons, and electrons.

Inside an atom

Atoms consist of three types of particle. At the center is a nucleus made up of protons, which have a positive electric charge, and neutrons, which have no charge.

This is orbited by some even smaller negatively charged particles called electrons, which spin around the nucleus at great speeds.

These particles are so tiny that most of an atom is actually just empty space.

Different atoms

A helium atom has just 2 protons, 2 neutrons, and 2 electrons, while a magnesium atom has 12 of each. Sometimes atoms can lose or gain electrons to become a special type of atom called an ion. When an atom loses electrons, it becomes a positively charged ion. If it gains electrons, it becomes a negatively charged ion.


Scientists can learn more about atoms by smashing subatomic particles into each other at high speeds and then studying the results.

They do this using machines called particle accelerators, such as the Large Hadron Collider (below) at CERN in Switzerland.


Scientists smash atoms together at close to the speed of light to split them into smaller, subatomic particles

Subatomic particles, such as electrons, are not usually visible. However, inside this special bubble chamber filled with liquid hydrogen, the electrons leave behind tracks as they move, creating intricate spiral patterns