An ion is an electrically charged atom or molecule. In the neutral state atoms or molecules have exactly as many electrons as protons. The electric charge, and thus the ion, is created when an atom or molecule has either more or less electrons compared to the neutral condition. Ions are positively charged if they have an electron deficiency and negatively charged if they have more electrons. Because of their electrical charge, ions can be bundled and accelerated to high speeds in an ion beam using ion sources and particle accelerators.