Atom is a chemical unit of an element; consists of electrons moving rapidly around a dense nucleus composed of protons and neutrons; an atom is classified by the number of protons and the number of neutrons contained in its nucleus.
An atom is the smallest unit of ordinary matter that forms a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are extremely small, typically around 100 picometers across.…