Anion: Definition & Examples

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  • 0:01 Sub-Atomic Particles & Ions
  • 1:10 Formation of Anions & Salts
  • 1:52 Biologically Important Anions
  • 2:55 Lesson Summary
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Lesson Transcript
Instructor: John Williams
Ions are charged particles that are important for biological and chemical systems. Anions are ions that have a negative charge. This article discusses anions, their properties, and examples of anions in chemistry and nature.

Sub-Atomic Particles and Ions

To talk about ions, we first need to review atoms. An atom is the smallest unit of matter. It consists of three sub-atomic particles:

  1. Protons are positively charged particles found in the nucleus (or core) of the cell.
  2. Neutrons are neutrally charged particles, and contribute to the overall mass and size of the atom.
  3. Electrons are negatively charged particles that orbit, or circle, the nucleus.

In a neutral atom, the number of protons will equal the number of electrons. This means that for every positive charge, there is a negative charge to balance it out. However, in some cases, the number of protons will not equal the number of electrons, and this will create an imbalance in the atom's charge and will form an ion.

Ions are atoms or molecules that have an electrical charge. These charged particles have chemical properties that allow them to form many important chemical molecules, such as salts, which are vital for biological systems. Ions can have either a positive or negative charge. Ions with a negative charge are known as anions. Let's discuss how ions, specifically anions, are formed.

Formation of Anions and Salts

Since anions are negatively charged particles, the number of electrons must be greater than the number of protons. This may occur when the atom receives an electron from another atom or molecule. This negative charge will now allow anions to attract and interact with positive ions (cations).

When anions form bonds with cations, they form salts. Salts are inorganic molecules (lacking carbon, hydrogen, or both) that dissolve well in water, separating into anions and cations. In solution, these ions are also called electrolytes, which means they carry electric charges. These are the same electrolytes advertised as being in Gatorade, Powerade, and other exercise drinks.

Formation of Ions

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