When substances involved in chemical bonding yield compounds, the stability of the resulting compound is measurable by the type of chemical bond they incorporate.

The type of chemical bonds formed varies in strength and properties. There are four primary forms of chemical bonds formed by atoms or molecules to produce compounds. These forms of chemical bonds include:

• Ionic bond: Ionic bonding is a form of chemical bonding that involves the movement of electrons from one atom or molecule to another. Here, an atom sacrifices an electron and is, in essence, taken by another atom. When such an electron transfer occurs, one of the atoms produces a negative charge, which is considered an anion. The other atom has a positive charge and is called the cation. The ionic bond, also known as the electrovalent bond, derives strength from the difference in charge between the two atoms, i.e., the higher the difference in charge between the cation and the anion, the stronger the ionic bond. The resultant is thus known as ionic compounds.
• Covalent bond: The covalent bond implies the distribution of electrons between atoms. Compounds that contain carbon (also known as organic compounds) typically exhibit this form of chemical bonding. The pair of electrons shared by the two atoms now extends around the nucleus of the atoms, contributing to the formation of a molecule (covalent compounds).
• Hydrogen bond: Hydrogen bonding is a weaker type of chemical bonding. It is a kind of polar covalent bonding between oxygen and hydrogen in which hydrogen develops a partial positive charge. It means that the electrons draw closer to the more electronegative oxygen atom.

Such bonds in chemical bonding form by the loss, gain or exchange of electrons between two atoms/molecules.

Ionic bonds, also called an electrovalent bond, are created by electrostatic attraction between oppositely-charged ions in a chemical compound. Such a bond forms when one atom’s valence (outer) electrons permanently pass to another atom.

Compounds containing ionic or electrovalent bonds are called electrovalent or ionic compounds. Electrovalent compounds form due to reactions between highly electronegative atoms and highly electropositive atoms. These compounds form by the attraction of oppositely charged particles (ions) during any reaction – anion (negatively charged ion) and cation (positively charged ion) are kept together by the electrostatic force of attraction. They are thus the most stable species of compounds in general.

A co-ordinate bond, referred to as a dative covalent bond, is a covalent bond with a typical pair of electrons in which all electrons originate from the same atom. The covalent bond is formed by two atoms that share a pair of electrons. The atoms lie together, and both the nuclei attract the electron pair.

Covalent compounds are chemical compounds in which a lot of atoms are all bound together by covalent bonds. The characteristic properties of covalent compounds are as follows:

• The majority of covalent compounds have comparatively low melting points and boiling points.
• Covalent compounds happen to be soft and very flexible.
• They are bad conductors of electricity.
• They have lower fusion and vaporisation enthalpies.
• Covalent compounds happen to be more flammable than ionic compounds.

In this chapter, we learned about the basic concepts of Force, Work, Energy and Power. We learned about theaThis unit highlights the fundamentals of chemical bonding. We also gathered an understanding of bonds such as ionic bonds, the structure of electrovalent compounds and their associated concepts. types of forces and the energy conservation principle.

1. Why do the atoms react, and how?
2. Atoms with eight electrons in their last orbit are stable and cannot react. Atoms with fewer than eight electrons react with other atoms to have eight electrons in their outer orbit and become stable. Atoms having more than eight electrons can lose them to atoms that are short of eight.
5. Name the forces that hold the atoms reacting together.
6. Atoms that lose and gain electrons become ions and are kept together by the electrostatic forces of attraction (Ionic Bond). As atoms give and exchange electrons equally, the exchanged electrons are the unifying force between them (covalent bond). The exchanged electron bridges the electron-rich atom to the electron-deficient atom (co-ordinate bond).
9. How can you recognise an ion bond?
10. There is an ion bond between a metal and non-metal and a covalent bond between two non-metals.
13. Which is the stronger ion bond or the covalent bond?
14. Covalent is better since the two atoms hold two or three external shell electrons. When an external shell electron of valence passes from one atom to another, ion bonds are created-a much weaker interaction.
17. Why are ionic bonds not true bonds?
18. Ionic bonds form by the complete transition of electrons forming a cation and anion from one atom to another. It creates a strong force of electrostatic attraction between the ions. Because of the formation of electrostatic attraction alone, it is not considered to be a true bond.