<Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (June 2016) (Learn how and when to remove this template message) </Td> </Tr> <P> 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 . A plasma is 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 . </P> <Ul> <Li> protons and atomic nuclei </Li> <Li> positrons (antielectrons) </Li> <Li> alpha particles </Li> <Li> positive charged pions </Li> <Li> cations </Li> </Ul> <Li> protons and atomic nuclei </Li>

Who proposed the existence of a positively charged particle