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What Is An Ion? Anions And Cations

What is an ion? Anions and cations

An ion is an atom or group of atoms (molecule) that does not have a neutral electric charge. A positively charged ion is called a cation, and a negatively charged ion is an anion. So, they may be positive or negative.

The word ion comes from de Greek word ἰόν.

There are two kinds of ions:

  • Anions.
  • Cations.

Cations and anions are usually represented with the symbol of the corresponding atom and the symbol "+" or "-". Cations +. Anions negatively -.

If the number of electrons gained or lost is greater than one is also indicated.

Ions are divided into:

  • Monatomic. It is made up of one atom.
  • Polyatomic. It is made up of two or more atoms.

Michael Faraday was the first to propose its existence. It was in 1830. Later, Arrhenius developed the corresponding theory in 1884. He won the Nobel Prize in Chemistry in 1903.

What is ionization?

Ionization is the phenomenon by which the number of electrons of an atom changes. It may lose or gains one or more electrons.

Fully ionized atoms are commonly called charged particles. Like those of alpha particles. Ionization is generally done by applying high energy to atoms. In the form of electric potential or radiation.

An ionized gas is called a plasma.

Some of the components resulting from nuclear fission reactions are highly ionized elements.

What are anions and cations? Ion types

There are two types:

  • Anions. Negative ions. They are attracted by the anodes.
  • Cations. Positive ions. They are attracted to the cathodes.

The cations are attracted to the cathode. Anions are attracted to the anode.

The anode and cathode

A cathode is an electrode that undergoes a reduction reaction, whereby a material reduces its oxidation state by receiving electrons.

The anode is an electrode in which an oxidation reaction occurs. Through this reaction a material, by losing electrons, increases its oxidation state.

What is ionization energy?

Ionization energy is the energy required to remove electrons from an atom. Also called ionization potential.

For individual atoms in a vacuum, there is a physical constant associated with the ionization process. These terms are also used to describe the ionization of molecules and solids. However, the values ​​are not constant. Ionization is influenced by local chemical bonds, geometry, and temperature.

First ionization energy

Ionization energy is the energy required to remove an electron. The second ionization energy is required to remove two electrons. And so in the following. Subsequent ionization energies are always quite larger than previous ones.

Ionization potentials are gradually increasing. Generally, there is a huge jump in energy at some point in the series. This causes each atom to tend to form a certain type of cation.

This is why ions tend to form in certain ways.

For example, sodium is found as Na +, but not normally as Na 2+. This is due to the high second required energy. It is much higher than the first. Similarly, magnesium is found as Mg 2+ and not Mg 3+, and aluminum exists as a 3+ cation.

Ionization potentials decrease from top to bottom. They grow from left to right on the periodic table. This trend is inverse of that found for the atomic radius.

What is an ion? Anions and cations

This is because, in small atoms, the electrons are more strongly attracted to the nucleus. Also, there is more energy to pull them out.

What is ionizing radiation?

Ionizing radiation is radiation that has a frequency large enough to ionize the atoms or molecules of the exposed substances. This type of radiation is capable of modifying the chemical structure of the substances on which they affect. They can also produce long-term biological effects on living things.

An example of ionizing radiation would be modifying the DNA of cells, these DNA mutations can lead to cancer. X-rays and gamma radiation would be two examples of highly ionizing electromagnetic radiation.

What is non-ionizing radiation?

Non-ionizing radiation is radiation that does not have enough frequency to cause ionization of exposed materials. As an example of non-ionizing radiation, microwaves, or radio waves can be mentioned.

This type of radiation does not have enough energy to directly cause DNA mutations.


Published: September 7, 2015
Last review: March 26, 2020