Ionic Bonding: Definition, Factors, Properties & Examples

What is an ionic bond?

How do we hold different ions together? We may have come across such questions while dealing with the Chemistry subject. It is a fundamental topic that every chemistry enthusiast should know.

In ionic bonding, a simple process takes place. It starts by forming a bond between one or more than one atoms. After that, using that atom bondage as a bridge, electrons are transferred from one atom to another. So, this is what happens inside an ionic bond.

This article will provide further knowledge regarding ionic bonds while having a good look at other related concepts.

Ionic Bond Definition

When two or more oppositely charged ions are held together due to the presence of electrostatic force, the resulting bond is termed an ionic bond. Simply put, a chemical bond will be formed among two atoms by transferring one or more electrons from one atom to another. Due to this bondage, the atoms are capable of obtaining their inert gas configuration.

In order to lose energy to become stable, there are three ways the atoms could follow. The most commonly used way is when atoms donate or accept electrons from neighboring atoms to accomplish their octet configuration. Hence, a bond formed due to this type of configuration is called an electrovalent or ionic bond.

In the majority of cases, one atom loses electrons while the other gains them. It happens in the outermost layers of an atom.

Ionic Bonding Diagram

Let us have a look at the ionic bonding diagram below:

From this diagram, one can easily understand that an ionic molecule is formed when a metal atom transfers its electrons to a non-metal atom. 

Electrovalent Bond

While transferring electrons from one atom to another, bonds are formed. These bonds are referred to as electrovalent bonds or ionic bonds. They will contain positive and negative ions. Usually, electrovalent bonds are formed only between non-metals and metals. Also, it is impossible to form a bond between two non-metals.

In other terms, one can simply say that the electrovalent bond is formed when there is a transfer of a certain number of electrons from one atom to another dissimilar atom. They both should possess opposite characteristics, such as the donor atom should contain the electrons. In contrast, the receiver atom should have the required holes in it to accept the donating electrons. Due to this process, both electrons obtain a stable inert gas configuration.

The acquired electrostatic attraction always has the tendency to decrease the potential energy. Therefore, as a result, the system’s potential energy is way less than before.

Ionic Bonding and Electronegativity

• An ionic or electrovalent bond is formed while transferring valence electrons to acquire stability completely.
• Due to this kind of bonding, two oppositely charged ions are formed. They are called anions and cations. Anions are negative ions, while cations are positive ions.
• A strong, attractive force will be formed between the two oppositely charged ions. This force is called an electrovalent or ionic bond.
• When the atoms consist of huge differences in electronegativity, ionic bonds are formed. On the other hand, when the difference is smaller, covalent bonds are formed.
• Furthermore, ionic compounds are compounds formed by the electrostatic attraction of negative and positive ions.

Electronegativity

It is nothing but the tendency of an atom to attract the electron-shared pairs towards itself is called electronegativity. Electronegativity is a dimensionless property because it does not involve any dimension and is only a capability.

The main purpose of electronegativity is to indicate the net outcomes of atoms’ tendencies in multiple elements to attract the electron pairs that possess bond-forming. Electronegativity can be measured on different scales; however, the most common scale used to measure is the one designed by Linus Pauling.

Factors affecting Electronegativity

Various phenomena influence electronegativity. The following are some of them:

1. Nuclear charge:

A nuclear charge simply means the charge of protons present in the nucleus of an atom. The higher the number of protons inside the nucleus, the higher the nuclear charge. If the value of the nuclear charge is higher, then the value of electronegativity is also greater. Due to the increased nuclear charge, there will be an electron attraction with greater force.

2. Atom’s size:

The size of an atom depends on the electrons present in the outer layers. If the layers increase, the atomic size will also increase. The increased atomic size will result in decreased nuclear charge because it makes it hard for the protons to balance the atom. Since electrons are situated far away from the nucleus, they will only experience lesser attraction. Therefore, the greater the atomic size, the lesser the electronegativity value will be. 

3. Effect of Substituent:

The atom’s electronegativity mainly depends on the substituent nature attached to that atom. For instance, the carbon atom in CF₃ I will obtain a greater positive charge than CH₃I. It indicates that the carbon atom in CF₃ I contains higher electronegativity compared to the one in CH₃I. 

Hence, an atom’s electronegativity difference caused by substituents will result in varied chemical behavior.

 Difference between Ionic Bond and Covalent Bond

There are a considerable number of differences found between ionic and covalent bonds. The following tabulation will provide details about the same:

Ionic bond	Covalent bond
An ionic bond is described as an attraction between positively and negatively charged ions in atoms. When these ionic bonds hold compounds together, they are called ionic compounds.	When two atoms share one or more electron pairs, the bond formed is called a covalent bond. Every electron will contribute the same amount of electrons for forming the bond.
The atoms that contain enormous electronegativity differences are capable of forming ionic bonds.	While combining the atoms, if the electronegativities do not see much difference, then the formation of a bond will be covalent.
Ionic compounds are formed when the ionization potential difference between two atoms is considerably higher.	The atoms that possess higher ionization potential cannot lose their valence electrons; therefore, they form covalent bonds simply by sharing electrons.
An example of an ionic bond is NaCl.	An example of a covalent bond is HCl.

Properties of Ionic Bond

There is a strong force of attraction between the anions and cations in the ionic-bonded molecules. Due to that reason, the following properties are used:

• The ionic-bonded ones have higher boiling and melting points than other molecules.
• It is proven that ionic bonds are considered the strongest of all bonds.
• Ionic bonds contain charge separation. Therefore, inside the proper medium, they are the most reactive bonds.
• When these molecules are kept in their molten state or aqueous solution, they act as excellent conductors of electricity. The main reason for that is due to the presence of ions capable of acting as charge carriers.

Ionic Bond Examples

The below-mentioned table provides the details on how the ions and elements are formed when they gain or lose an electron:

Element	Electronic configuration	Reaction	Formed ion
Na (11)	2, 8, 1	Reaction 1: Na → Na++e–	Na+
Ca (20)	2, 8, 8, 2	Reaction 2: Ca → Ca2++2 e–	Ca2+
Cl (17)	2, 8, 7	Reaction 3: Cl+e– → Cl–	Cl–
O (8)	2, 6	Reaction 4: O+2e–→ O2–	O2-

• Therefore, reactions 1 and 3 will occur when Na reacts with Cl. In that, the resultant compound can be found as NaCl.
• In addition, if Na reacts with O, the possibilities of reactions 1 and 4 taking place are higher. Hence, their resultant compound is Na₂.
• Moreover, when Ca and Cl react with each other, reactions 3 and 2 will happen. In that, the resultant compound can be CaCl₂.
• When Ca reacts with O reactions 2 and 4 will occur. Therefore, the resultant compound would be CaO.

 These are some ionic bond examples that everyone should be aware of while studying this topic.

Conclusion

To conclude, we have gone through various concepts concerning ionic bonding, such as what is an ionic bond, ionic bond definition, ionic bond examples, and ionic bonding diagram. Hence, anyone who reads this article can simply understand the basic concepts of ionic bonds.

Frequently Asked Questions

1. What happens in an ionic bond?

The sole purpose of ionic bonding is to transfer valence electrons from one atom to another. It can be seen as one type of chemical bonding that could generate two oppositely charged ions. In general, the metal loses its electrons in order to become a cation (positively charged ion). In the meantime, the non-metals receive those electrons in order to become an anion (negatively charged ion). 

2. How can we identify an ionic bond?

One of the simplest ways to determine an ionic bond is by verifying whether the chemical compound is made of two electrons; in that, one has to be a non-metal (belonging to groups 5, 6, or 7), and the other one should be a metal, belonging to the group 1, 2 or 3.

3. How is a covalent bond made?

   In covalent bonds, there will be a mutual sharing of one or more electrons present among two atoms. The two nuclei of atoms consecutively attract both these electrons. A covalent bond can be obtained if the difference between both the atoms’ electronegativities is too small so that the transfer of electrons does not take place in order to form ions.