Definition Of Covalent Bond
It is a chemical bond formed between atoms by sharing of electron pairs.
More About Covalent Bond
- The state balance of attractive forces and Repulsive forces between atoms when they share electron pairs is known as Covalent bonding
- An atom share electron with another atom of same or different element in order to attain stable electronic configuration of nearest inert gas i.e. Helium ,neon ,argon ,krypton ,xenon and Radon
- Covalent compounds have low melting and Boiling points. For example boiling point of chloroform is 60OC.This is due to weak forces of attraction between molecules
- Covalent compounds are non-conductors of electricity. This is due to the absence of free ions
- In a covalent bond shared pair of electrons is known as Bond pair. Bond pair is represented by a line
- Depending on number of electrons shared between atoms, Covalent bonds are classified into three types: Single covalent bond, Double covalent bond and Triple covalent Bond
Examples of Covalent Bond
Formation of Hydrogen molecule is an example of single covalent bond. We know that atomic number of Hydrogen is 1.That means hydrogen atom contain one proton in its nucleus and one electron in its shell. Hydrogen atom requires one more electron to attain nearest stable electronic configuration of inert gas (Helium).To achieve this two hydrogen atoms share one electron each to form a single covalent bond.
Formation of Oxygen molecule is an example of Double covalent Bond. The atomic number of oxygen is 8.That means oxygen atom contains 8 protons in its nucleus and it has 2 electrons in first shell and 6 electrons in second shell. Oxygen atom requires two more electrons to attain stable electronic configuration of nearest inert gas (Neon).Oxygen atom combines with another oxygen atom and share two electrons each to form a double covalent bond between two oxygen atoms.
Formation of Nitrogen molecule is an example of Triple covalent bond. Atomic number of nitrogen is 7.That means Nitrogen atom contains 7 protons in its nucleus, 2 electrons in its first shell and 5 electrons in second shell. Nitrogen atom requires 3 more electrons to attain stable electronic configuration of nearest inert gas (Neon).Nitrogen atom shares three electrons with another nitrogen atom and forms Triple covalent bond.
Other examples of covalent Bond are Methane, chloroform, carbon tetrachloride, Bromine, chlorine, Carbondioxide, Sulphuricdioxide, Sulphur trioxide, acetylene etc.
Solved Example:
Ques: Which of the following compound is formed by covalent Bond?
- A. Sodium chloride
B. Carbon dioxide
C. Magnesium chloride
D. Potassium chloride
Answer : Carbon dioxide is formed by the double covalent bonding between carbon and oxygen. Remaining compounds are formed by ionic bonding