Definition - What does Cation mean?

A cation is an ion or group of ions possessing a positive charge and having the natural ability to move toward the negative electrode in electrolysis.

A corrosion reaction involves dissolution of metal into its respective ions. Therefore, the rate of reaction depends entirely on the formation of ions in the electrochemical cell.

Corrosionpedia explains Cation

In an atom or molecule, if the number of electrons is equal to the total number of protons, the atom is said to be neutral. However, when electrons are not equal to protons, an atom or molecule has a net positive or negative electrical charge.

Charges on atoms can be developed by both chemical and physical means. When an atom loses one or more electrons it attains a positive charge and is known as a cation. When it gains electrons, it has a negative charge, and is considered an anion.

Elements in group I-A lose one electron and become cations with a single charge. These ions include:

  • Lithium ion
  • Sodium ion
  • Potassium ion

Elements in group I-A lose two electrons and become cations with a charge of two. These ions include:

  • Beryllium ion
  • Magnesium ion
  • Calcium ion

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