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Learning about Covalent Bonding - Chemistry Revision


Chemical bonding is divided into three major categories- Ionic, Covalent and Metallic Bonding. Covalent bonding takes place between non metals and it involves sharing of electrons. Covalent bonding, which is also known as molecular bonding, is formed by the sharing of electron or electron pairs between the atoms. Electrons are also called bonding pairs here. They do not transfer electrons as seen in ionic bonds but share.

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When the atoms share electrons there is a stable balance of the attractive and repulsive forces. This bond is called a covalent bond and the two atoms bonded together are called covalent molecules. It is formed between the non-metal atoms.
Example – CO2


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Since these atom share electrons and don't transfer so there is no free electron or ions present in the atoms. Hence they do not conduct any electricity. In the periodic table elements are arranged according to their Atomic number and the elements present in the same vertical column are said to belong to the same family so they have similar chemical properties. Some elements are stable by forming diatomic molecules while some are stable forming polyatomic molecules as shown in the diagram.


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Covalent compounds are either liquid or gasses so they have a very low melting or boiling point and they do not conduct electricity.
Example:

  • Carbon dioxide (CO2): The boiling point is -44 degrees and it doesn't conduct electricity.
  • Water (H2O): The melting point is 0 degrees and it doesn't conduct electricity.


Dot Cross Diagram of Covalent Molecules 

Water (H2O)

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Hydrogen (H2)


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Methane (CH4)
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Chlorine (Cl2)


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Properties of Covalent Bonding

On the basis of bonding and structure, the properties of covalent molecules can be explained like Low melting points, low boiling points and poor conductor of electricity. 

Low melting and boiling points

The intermolecular forces binding the two atoms are very weak in covalent bonding hence very low temperature is required to either melt or boil the molecule and separate the atoms. So they have a low melting and boiling points.

Non conductors

Covalent molecules share the electron with each other so there is no free electron present on the atoms hence they cannot conduct electricity.
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