Chemistry – Atoms, elements and compounds - Ions and ionic bonds | e-Consult

Metals form positive ions (cations) by losing one or more electrons. The electrons are typically lost from the outermost shell (valence shell) which are loosely held. This process results in the metal atom having more protons than electrons, giving it a positive overall charge. The number of electrons lost determines the charge of the cation. For example, sodium (Na) readily loses one electron to form a sodium ion (Na⁺), a +1 cation. Magnesium (Mg) loses two electrons to form a magnesium ion (Mg²⁺), a +2 cation. The electronic changes involve the formation of a filled electron shell, which is a stable configuration. The tendency of metals to lose electrons and form positive ions is a key characteristic of their chemical behaviour.

• Metals lose electrons from their outermost shell.
• This results in a positive charge on the atom.
• The number of electrons lost determines the cation's charge.
• This process leads to a stable, filled electron configuration.