Ions

When atoms have an equal number of protons and electrons, they are neutral and have no electrical charge. However, both man-made and natural forces can act on atoms and result in a gain or loss of electrons.

Positive Ion
Positive Ion.

When a neutral atom has lost an electron (which is negatively charged), the positively charged protons now outnumber the electrons, giving the atom a positive charge. The now positively charged atom is called a positive ion, or a cation.

When a neutral atom has gained an electron (which is negatively charged), the electrons now outnumber the positively charged protons, giving the atom a negative charge. The now negatively charged atom is called a negative ion, or an anion.

Negative Ion
Negative Ion.

There are several forms of energy that can force atoms to give up electrons. These include:

  • Chemical energy
  • Electrical energy
  • Heat energy
  • Mechanical energy
  • Nuclear energy
  • Ionizing radiation