Carbon and Its Compounds Types of Covalent Bond
These notes are based on the chapter Carbon and its Compounds from class 10 science of NCERT book and CBSE syllabus.
Covalent Bond: A bond formed by sharing of electrons is called covalent bond. It is important to remember that electrons are always shared in pairs. Following are different types of covalent bond.
- Single Bond
- Double Bond
- Triple Bond
Single Bond
Single covalent bond is formed because of sharing of two electrons, one from each of the two atoms.
Formation of hydrogen molecule (H2)
Atomic Number of H = 1
Electronic configuration of H = 1
Valence electron of H = 1
Hydrogen forms a duet, to obtain stable configuration. This configuration is similar to helium (a noble gas).
Since, hydrogen has one electron in its valence shell, so it requires one more electron to form a duet. So, in the formation of hydrogen molecule, one electron from each of the hydrogen atoms is shared.
Formation of hydrogen chloride (HCl)
Valence electron of hydrogen = 1
Atomic number of chlorine = 17
Electronic configuration of chlorine: 2, 8, 7
Electrons in outermost orbit = 7
Valence electron = 7
Formation of chlorine molecule (Cl2)
Valence electron of chlorine = 7
Formation of water (H2O)
Valence electron of hydrogen = 1
Atomic number of oxygen = 8
Electronic configuration of oxygen = 2, 6
Valence electron = 6
Oxygen in water molecule completes stable configuration by the sharing one electron from each of the two hydrogen atoms.
Formation of Methane (CH4)
Valence electron of carbon = 4
Valence electron of hydrogen = 1
Formation of Ethane (C2H6)
Double Bond
Double bond is formed by sharing of four electrons, two from each of the two atoms.
Formation of oxygen molecule (O2)
Valence electron of oxygen = 2
In the formation of oxygen molecule, two electrons are shared by each of the two oxygen atoms to complete their stable configuration.
In oxygen, the total number of shared electrons is four, two from each of the oxygen atoms. So a double covalent bond is formed.
Formation of Carbon dioxide (CO2)
Valence electron of carbon = 4
Valence electron of oxygen = 6
In carbon dioxide two double covalent bonds are formed.
Formation of Ethylene (C2H4)
Valence electron of carbon = 4
Valence electron of hydrogen = 1
Triple Bond
Triple covalent bond is formed because of the sharing of six electrons, three from each of the two atoms.
Formation of Nitrogen (N2)
Atomic number of nitrogen = 7
Electronic configuration of nitrogen = 2, 5
Valence electron = 5
In the formation of nitrogen, three electrons are shared by each of the nitrogen atoms. Thus one triple bond is formed because of the sharing of total six electrons.
Formation of Acetylene (C2H2)
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