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Ionic bond

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Definition

noun

plural: ionic bonds


A type of chemical bond in which atoms, ions, or molecules are held together by electrostatic attraction


Details

Overview

A chemical bond holds atoms, ions, or molecules together. Three types of chemical bonds that are biologically important are (1) ionic bonds, (2) covalent bonds, and (3) hydrogen bonds.


Ionic bond - characteristics

Electron transfer

An ionic bond is a chemical bond wherein there is a transfer of an electron from one atom to another. For an ionic bonding to occur there must be an electron donor (often a metal) and an electron acceptor (often a nonmetal). The transfer of electrons is referred to as electrovalence. The atom that loses one or more electrons will turn into a positive ion and will be called a cation. The other atom that gains one or more electron will become a negative ion and will be referred to as an anion. The ion that receives the electron is named by changing the elemental name with an -ide in the end. For example, chlorine anion will be called chloride whereas sulfur anion, sulfide.


Electrostatic attraction

Ions or atoms of opposite charges tend to be attracted towards each other. This is as opposed to the phenomenon wherein ions or atoms with the same charge tend to repel. In this case, this is called electrostatic repulsion. In ionic bond, an electrostatic attraction works between oppositely charged ions where anions are chemically attracted to cations. The strength of this attraction depends on the size of the atom's charge, the distance between two atoms, and other forces acting on the atoms.


Zero net charge

The electron that can be donated or accepted may be more than one as long as the octet configuration is achieved. Thus, it can be expected that the net charge of the resulting compound (i.e. ionic compound) will be zero (0), and will be in crystalline form.


Ionic compound

Chemical bonds, such as ionic bonds, help form a chemical compound. A chemical compound is a substance comprised of more than one type of atoms. Thus, a substance that is made up of only one type of atom is not a compound but a chemical element.


A chemical compound in which the bond that holds atoms or particles together is called an ionic compound. An example of an ionic compound is the sodium chloride, NaCl. It is made up of a cation (Na+) and an anion (Cl-) held together by an ionic bond.


An ionic compound will be made up of both positive and negative ions. Therefore, the oppositely charges ions in an ionic compound combines and balancing each other out resulting in a net charge of zero (0).


An ionic compound that has hydrogen ions (H+) is classified as an acid. Conversely, an ionic compound that has hydroxide (OH-) or oxide (O2-) is classified as a base. An ionic compound formed by acid-base reactions and without those ions is called a salt.


Ionic bond vs. Covalent bond

While covalent bond involves the sharing of electrons between atoms, an ionic bond involves the transferring of electrons from one to another in order to achieve the stable configuration.

Here is a tabulated summary of the major differences between ionic bond and covalent bond:[1]

Ionic bond Covalent bond
formation Ionic bond is formed by the transfer of electrons between atoms of one metal and one non-metal. The compound that results in an ionic bond is called ionic compound. Covalent bond is formed by the sharing of electrons between atoms of two elements, such as between two non-metals.
electronegativity (i.e. the ability of an atom to attract electrons towards it) The strong electronegativity of one atom attracts electron(s) from another atom. The atom that is strongly electronegative can gain electron(s) and becomes an anion. Conversely, the atom that is weakly electronegative loses electron(s) and becomes a cation. electronegativity of one atom is not strong enough or is somewhat the same as that of another atom, thus, the atoms tend to share rather than get or give electrons to achieve a stable electron configuration
salt formation The electrostatic attraction between anion and cation forms an ionic compound. Many of the ionic compounds are referred to as salts since they can be formed by the neutralization reaction between a base (e.g. OH-) and an acid (H+). The bond that forms between the atoms does not result in the formation of a salt.
state at room temperature solid, with a crystallographic lattice liquid or gaseous
polarity high low
types - single bond, double bond, triple bond


It is argued that no absolute transferring of electrons exists and that an ionic bonding has some sort of covalent character in it. Nevertheless, a chemical bond that appears to be more of an ionic than a covalent, then it is deliberated as an ionic bond. One of the ways to tell that a bond is ionic is by looking at the electronegativity. The larger the difference in electronegativity between the two atoms is, the more ionic it is.


Ionic bond vs. Hydrogen bond

As the name implies, a hydrogen bond is a chemical bond wherein hydrogen serves as a bridge between two atoms. Similar to the ionic bond, the hydrogen bond entails an electrostatic force. Hydrogen bond forms when the slightly positive hydrogen atom of a polar covalent bond forms an electrostatic link with the more electronegative atom of a polar covalent bond in the same or another molecule.


The hydrogen bond, though, is a weaker chemical bond than ionic bonds at most. Nevertheless, the hydrogen bond is still essential to organisms as it is responsible for the formation of the secondary and the tertiary structures of nucleic acids and proteins.


Supplementary

Synonym

  • electrovalent bond


Further reading

Compare

See also


Reference

  1. Covalent Bonds vs Ionic Bonds. (13 January 2017). Retrieved from [Link]



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