What is the mass of an electron?

The mass of an electron is approximately 9.11 x 10^-31 kilograms or 0.00054858 atomic mass units (amu). It is one of the three fundamental subatomic particles, along with protons and neutrons, that make up atoms. Electrons are negatively charged particles that orbit the atomic nucleus and participate in chemical reactions. The mass of an electron is much smaller than the mass of a proton or neutron, which are approximately 1.67 x 10^-27 kg or 1 amu each. The mass of an electron is also a fundamental constant in physics and is used in various equations and calculations in quantum mechanics and other areas of physics.