Which particle carries a negative electric charge?

The electron carries a negative electric charge.

Electrons are elementary particles found in atoms and belong to the lepton family. In an electrically neutral atom, the number of electrons equals the number of positively charged protons in its nucleus. Removing or adding electrons produces an ion.

In many solids, especially metals, some electrons can move through the material. Their movement forms an electric current, although conventional current direction is defined as the direction positive charge would move. Therefore, electron flow in a metal is opposite to conventional current direction.

The electron’s charge has the same magnitude as the proton’s charge but the opposite sign. A positron is the electron’s antimatter counterpart and has positive charge. A neutron has no net electric charge. J. J. Thomson’s 1897 cathode-ray experiments provided key evidence for electrons as universal constituents of matter.