Last update: Dec 2nd, 2017

Ions – Cations and Anions

• Many types of ions are dissolved in the water environment that surrounds the neuron cell membrane.

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• Ions are charged particles that form when atoms and molecules gain or lose one or more electrons.

• Atoms or molecules that lose electrons become positively charged and are called cations.
• In contrast, those that gain electrons become negatively chargedand are called anions.

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• In a water environment there are many ions. Sodium (Na+) , Potassium (K+), Calcium (Ca+2), Chloride (Cl-), and proteins (-) are the most common.
• Ions attract nearby polar water molecules.

• The resulting hydration layers keep anions and cations separated, which allows the ions to remain dissolved in the water.

• If the hydration layers are removed, molecules such as NaCl (sodium chloride) or KCl (potassium chloride) will form due to ionic bonding between the anions and cations.