Read to know why do atoms form chemical bonds? Atoms tend to form bonds to move towards stability, in accordance with the octet rule. There are various types of bonds as listed below.
1. Ionic Bond
Ionic bonds are formed when one of the atoms shares its electrons with the other and reaches a stable octet. This is why do atoms form chemical bonds. The formation of an ionic bond occurs between a metallic and a non – metallic atom i.e. the metallic atom transfers an ion/electron to non – metallic atom.
2. Covalent Bond
Covalent bonds are the classic examples of chemical bonding in which the valence electrons are shared between two atoms, following the octet rule. The valence electrons occur in the outermost shell, which interact as per the difference in electronegativity. An existing thumb rule is that they should have an almost similar electronegativity. The electron density between the atoms is attracted towards the nuclei of both the atoms, resulting in the sharing of electrons between the atoms. A covalent bond is directional in nature depending upon the overlapping of the orbit. Covalent bonds are more likely to be seen in non-metal atoms.
3. Hydrogen Bond
Hydrogen bonds occur when hydrogen is attached to any of the X atoms (for example – nitrogen and oxygen), which is attracted to the same X atom on the other side. (See Is NH3 polar or nonpolar?)
4. Van Der Waal Bond
Van der Waal interactions are the weak chemical bonds that occur due to polarisation between nearby particles, as a result of quantum dynamics. These chemical bonds have the weakest intermolecular forces. This is, however, contrary to the fact that hydrogen bonds are the strongest type of Van Der Waal interaction.
5. Stability of Chemical Bonds
The Stability goes on as Hydrogen bond > Ionic bond > Covalent bond > Van der Waal Interaction. The electronegativity differential is the cause for the highest stability of hydrogen bond. This chemical bond is a special type of dipole-dipole attraction between the molecules. The atom bonds with an extremely electronegative atom, providing a bond strength of around 4 kJ to 50 kJ/mole in a hydrogen atom.
6. Valence Electrons
Now that you know why do atoms form chemical bonds, let’s discuss valence electrons. The electrons which participate in the formation of chemical bonds are known as the valence electrons. The valence electrons depend on the group the compound is placed into. They contribute to the shared pair of electrons in a chemical bond. The atom having one or two chemical bonds tends to be more reactive in sharing the valence pair of electrons. The valence electrons vary as:
- Group I has 1 valence electron.
- Group II has 2 valence electrons.
- Transition metals of group III have 2 electrons with a few exceptions.
- Group III has 3 electrons.
- Group IV has 4 electrons.
- Group V has 5 electrons and so on till group 18, which has 8 electrons. They have a stable octet and a noble gas configuration. (See How many valence electrons does oxygen have?)
7. Difference Between Anion & Cation
A Cation is a positively charged ion that loses an ion during the formation of the bond. An anion is a negatively charged ion that gains an electron during the formation of a bond. The bond formation complies with the rules of octet formation.
8. Octet Rule
The Octet rule is the tendency of atoms to keep eight electrons in the valence orbit. The atoms tend to form either a duplet or an octet, preferably an octet and thus, the name. According to the rule, an atom has a stable electrical arrangement when it is surrounded by eight electrons. Noble gases do not form compounds because they have a full octet and therefore no charge.
9. Dipole Moment
The extent of polarity in a molecule is known as its dipole moment. The dipole moment depends on the separation of the charge i.e. the farther the charges are, the higher is the dipole moment. The dipole moment is the product of the charge separation to the distance between the charges. (See What is the Lewis structure of CH2O?)
Electronegativity is the tendency of an atom or a molecule to attract electrons toward, enabling bond formation. This is why do atoms form chemical bonds. An increase is seen across a period from left to right, with a decrease in atomic size and an increase in nuclear charge.