Point particle of point charges cannot be maintained in an equilibrium configuration solely by the electrostatic interaction of the charges. In quantum mechanics, there is a distinction between an elementary particle (also called "point particle") and a composite particle. An elementary particle, such as an electron, quark, or photon, is a particle with no internal structure. Whereas a composite particle, such as a proton or neutron, has an internal structure (see figure). However, neither elementary nor composite particles are spatially localized, because of the Heisenberg uncertainty principle. The particle wavepacket always occupies a nonzero volume. For example, see atomic orbital: The electron
Kennedy (given name) popular. In 1990, the United States Census Bureau undertook a study of the 1990 United States Census, and released a sample of data concerning the most popular names. According to this sample of 6.3 million people (who had 5,494 unique first names), "Kennedy" did not even appear among the 4,275 feminine names, or the 1,219 masculine names. Kennedy (given name) Kennedy is a unisex given name in the English language. The name is an Anglicised form of a masculine given name in the Irish language. According to Patrick Hanks and Flavia Hodges, the given name "Kennedy" is an Anglicised form