Electrons are negatively charged subatomic particles that are fundamental to the structure and function of matter. Synonyms for electrons include subatomic particles, negatively charged particles, atomic particles, and elementary particles. Other terms commonly used in scientific literature are e- (short for electron), electron cloud, and electron shell. In chemistry, electrons are often referred to as valence electrons, as they are responsible for the chemical properties of matter. In physics, electrons are also called leptons, which are a type of elementary particle, and they are grouped together with other particles, such as quarks, to form atoms. Regardless of the terminology used, electrons play a critical role in the behavior and properties of matter.