Which particle carries a negative electric charge?

The electron is the negatively charged particle in ordinary matter, orbiting the nucleus in a cloud rather than a neat circle. Its charge is equal in size but opposite in sign to that of the proton, so an atom with matching numbers of each is electrically neutral. Because electrons sit on the outside of an atom, they are the part that interacts with neighbours, and essentially all of chemistry is the story of electrons being shared, swapped or shifted between atoms. When electrons drift through a metal wire, that flow is an electric current, though by an accident of history the conventional direction of current was defined as running the opposite way. Electrons are also far lighter than protons and neutrons, by a factor of nearly two thousand, which is why almost all of an atom's mass is concentrated in the nucleus while almost all of its volume is empty space occupied by the electron cloud.

Static shocks happen when electrons rubbed onto one surface jump back across a gap all at once.