An electron is a subatomic particle that carries a negative electric charge. It is one of the fundamental particles that make up atoms, which are the basic building blocks of matter. Electrons are part of the family of particles known as leptons, which are elementary particles that are not made up of smaller components.
Electrons have a very small mass compared to protons and neutrons, which are the other two main types of subatomic particles found in atoms. Despite their small mass, electrons play a crucial role in the behavior of atoms and in various phenomena involving electricity, magnetism, and chemical reactions.
Electrons are arranged in energy levels or orbitals around the nucleus of an atom. These orbitals define the electron's energy and location within an atom. Electrons can move between different energy levels by absorbing or emitting energy in the form of photons. This movement of electrons is what gives rise to many physical and chemical properties of matter, including the formation of chemical bonds between atoms.
In summary, electrons are fundamental particles with a negative electric charge that orbit the nucleus of an atom and play a key role in various fundamental interactions and the behavior of matter.