What Exactly Is Antimatter?
Identical to matter in almost every way, antimatter is the opposite of the material that makes up the world around us. What makes antimatter distinct from regular matter is seen at the subatomic level - in the components that make up an atom. We know atoms are made of positive protons, negative electrons, and neutral neutrons. Antimatter is precisely the opposite. Positrons (the name for anti-electrons) have a positive charge, and antiprotons are all negative. Antineutrons, as you may have guessed, still have no charge. All of these antiparticles, however, have the same magnitude charge, the same mass, and several other qualities that are identical in every way but the sign in front of the number.
Not only are these antiparticles the opposites of our standard matter particles, they are also completely incapable of interacting with them. If a particle and its antimatter equivalent ever come into contact, they destroy each other completely, leaving only energy.