Subatomic particles. Computer artwork of a table of subatomic particles. The top six are quarks, which make up particles such as protons and neutrons. The symbols represent the six types (or flavours) of quark: up (arrow up), down (arrow down), charm (crescent), strange (question mark), top (white cap) and bottom (white base). The lower six are the leptons. Along the bottom row, from left: the electron, the muon, and the tauon. Each of these has an associated neutrino represented above it. The electron, muon and tauon all have the same charge (formally -1), but their mass increases from left to right. Neutrinos have no mass or charge."