Example of Anions and Cations

In General Chemistry, it is known that matter is supported by bonds between atoms, which can generate a network of atoms, in the case of pure metals and nonmetals, or even molecules, which, when accumulated, give consistency to the substance. In the case of the formation of molecules, there is the ionic bond, which consists of one of the atoms is responsible for giving up one or more electrons from its last shell, and the other atom performs the work of receive them.

the electrons have negative carge, consequently the receptor acquires a negative charge. The atom that makes the delivery acquires a positive charge when it gets rid of those electrons. This phenomenon of ionic bonding occurs in mostly inorganic substances, and in different frequencies between organic reactions.

The particle made up of the atom (s) with a negative charge is called an Anion.

And the particle that consists of the atom (s) with a positive charge is called a Cation.

Charged particles in general are called Ions.

Anions and Cations occur in compounds such as Binary Salts, such as Sodium Chloride (NaCl). Taking this example, an important detail will be explained. When writing the compound, you always start with the element with a positive charge. And what accompanies it in the end will be the negatively charged part. Thus it is known that Sodium (Na) is the element that carries a positive charge, and Chlorine (Cl) is the negatively charged one.

Another important issue is knowing how much positive or negative charge each atom carries. Another Binary Salt will be taken as an example, which is Calcium Chloride (CaCl₂). When writing the molecule of Salt, the number that defines the charge of the Calcium atom is crossed with the number of the charge of Chlorine.

According to the Periodic Table, Calcium has a +2 charge, and Chlorine has a -1 charge. Crossed, the number 2 will be put on Chlorine, and 1 on Calcium. CaCl remains₂.

This formula CaCl₂ It can also be understood like this: Since Chlorine is capable of receiving 1 electron, 2 Chlorine atoms are necessary to capture the 2 electrons of the last layer of Calcium.

In addition to Binary Salts, Anions and Cations are found in Hydracids, such as Hydrochloric Acid (HCl), in Oxyacids, such as Sulfuric Acid (H₂SW₄), in the Oxisales, such as Sodium Sulfate (Na₂SW₄).

In Hydrochloric Acid, the Cation is Hydrogen with +1 charge: H⁺¹, and the Anion is Chlorine, with charge -1: Cl^-1.

In Sulfuric Acid, the Cation is Hydrogen, with charge +1: H⁺¹, and the Anion is Sulfate, with charge -2: SO₄^-2.

In Sodium Sulfate, the Cation is Sodium with +1 charge: Na⁺¹, and the Anion is Sulfate, with charge -2: SO₄^-2.

It is noted in the previous examples that Binary Salts and Hydracids are the combination of only two different elements, (one with a positive charge and the other with a negative charge). And the Oxisales and Oxiácidos contain as anion a group of atoms. This group of atoms is called Radical.

The Radical in the previous cases includes several oxygen atoms, with a -2 charge, and another positive element that compensates only a part of that negative charge. The rest of the negative charge would be compensated by the Cation, properly.

There are not only negative radicals, but also positive ones, such as Ammonium Cation (NH₄⁺), in which the fourth Hydrogen generates an excess charge.

Dissociation in Aqueous Solution

When an ionic compound enters the solvent Water as solute, it tends to attack the ionic bond, separating the solute into anions and cations. Depending on the compound in question, speaking of the strength of the bond, it will be the ease and abundance of that dissociation. This phenomenon is used to conduct an electric current.

Electrochemical cells

Electrochemical Cells are the main devices that take advantage of ionic compounds in solution for the generation and continuity of electrical energy. Electrochemical Cells can be Galvanic or Electrolytic..

A Galvanic Cell is made up of a container with two different metals, immersed in an ionic solution, and separated from each other by a porous membrane. These metals are connected by a saline bridge, in its upper part, emerging.

The chemical reaction that occurs between the ions of the solution with the cations of the first metal is spontaneous. Anions with their excess negative charge contribute electrons to one of the metals. This metal will be called Anode, for receiving the Anions. Since opposite charges attract each other, the anode is assumed to have a positive charge.

The electrons travel through the metal, flow towards the salt bridge, until they reach the other metal, which acquires a negative charge with the flow of electrons. Thus, the cations of the solution that surround it, will take those electrons to compensate for their charge. This other metal will be called the Cathode.

An Electrolytic Cell has the difference that it includes a source of electric current, because the reaction is not spontaneously in the solution, and it takes some momentum to start the steady flow of electrons from the anode to the Cathode.

Examples of Anions

Chloride Cl^-

Iodide I^-

Sulfide^-2

Nitride N^-3

Hypochlorite ClO^-

Chlorite ClO₂^-

Chlorate ClO₃^-

Perchlorate ClO₄^-

Nitrite NO₂^-

Nitrate NO₃^-

Bisulfite or Acid Sulfite HSO₃^-

Sulfite SO₃^-2

Sulfate SO₄^-2

Permanganate MnO₄^-

OH hydroxide^-

Cr dichromate₂OR₇^-2

Chromate CrO₄^-2

Borate BO₃^-3

Oxalate C₂OR₄^-2

PO phosphate₄^-3

Examples of Cations

Ammonium NH₄⁺

Hydronium H₃OR⁺

Sodium Na⁺

Potassium K⁺

Calcium Ca⁺²

Magnesium Mg⁺²

Barium Ba⁺²

Aluminum Al⁺³

Cuprous Cu⁺¹

Cupric Cu⁺²

Ferrous Fe⁺²

Ferric Faith⁺³

Plumbous Pb⁺²

Lead Pb⁺⁴

Cadmium Cd⁺²

Titanium Ti⁺⁴

Galio Ga⁺³

Lithium Li⁺

Hydrogen H⁺

Beryllium Be⁺²