Liceo Scientifico Newton - Roma
The atom represents the fundamental building block of matter. Although the word atom comes from the Greek for indivisible, now we know that atoms are not the smallest part of matter. Atoms, in fact, are made from smaller subatomic particles. Inside an atom there is a small central nucleus made up of protons and neutrons, surrounded by electrons, arranged in different shells around it. Physicists constantly look for new particles. They have discovered that all the known matter particles are composites of quarks and leptons: in particular protons and neutrons are composed of even smaller particles called quarks while electron is the best-known lepton.