In
physics, a
charged particle is a
particle with an
electric charge. It may be an
ion, such as a
molecule or
atom with a surplus or deficit of
electrons relative to
protons. It can be the electrons and protons themselves, as well as other
elementary particles, like
positrons. It may also be an
atomic nucleus devoid of electrons, such as an
alpha particle, a
helium nucleus.
Neutrons have no charge, so they are not charged particles unless they are part of a positively charged nucleus.
Plasmas are a collection of charged particles, atomic nuclei and separated electrons, but can also be a gas containing a significant proportion of charged particles. Plasma is called the fourth state of matter because its properties are quite different from
solids,
liquids and
gases.