What is an Atom

ABSTRACT An atom a fundamental piece of matter (Matter is anything that can be touched physically). Everything in the universe (except energy) is made of matter, and, so, everything in the universe is made of atoms. Atoms are made out of three main parts: protons, neutrons and electrons. The idea that matter is made up of discrete units is a very old idea. There are lots of types of atoms and those types are called elements. When it comes to understanding atoms and the way they look and act, we only really need to know about protons, neutrons and electrons. But that's not really the end of the story.