system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is antimatter?
gpt
In the simplest sense, antimatter is particles with the opposite charge of their matter counterparts.

A proton has charge +1 and an antiproton has charge -1.

An electron has charge -1 and a positron has charge +1.

A neutron has charge 0 and an antineutron has charge 0.

A particle of matter can annihilate with its antimatter counterpart, at which point the total mass is "converted" to energy in the form of photons.

There's much more to it than that, but the rest isn't as ELI5-able.