Carbon and Its Compounds - Class 10th Science
Bonding in Carbon: The Covalent Bond
Atom of every element forms a bond in order to achieve the stable configuration or electronic configuration of its nearest noble gas.
How does the atom of Carbon form a stable electronic configuration to make its atom stable?
There are four electrons present in the outermost orbit of carbon. Thus, the valence electrons of the carbon are equal to 4.
The nearest noble gases of the atom of the element of carbon are Helium and Neon.
The number of electrons present in the outermost orbit of the atom of Helium = 2
And the number of electrons present in the outermost orbit of the atom of Neon = 8
Thus, carbon can achieve the stable configuration by either losing 4 electrons from its outermost orbit or by gaining four electrons to its outermost orbit.
Two ways to achieve the stable electronic configuration by the atom of the element of Carbon
Situation: (1) Losing of four electrons from the outermost orbit by the atom of carbon.
Losing four electrons to get stable electronic configuration by the atom of the element of Carbon
The atom of the element of carbon can achieve stable electronic configuration by losing four electrons present in its outermost orbit.
After the loss of four electrons present in the outermost orbit of the atom of the element of carbon, C4+ ion will be formed. In this way, the number of electrons in the outermost orbit of the carbon atom will become equal to 2, and the carbon atom can achieve the electronic configuration similar to Helium (He), which is a noble gas.
Consequences after the removal of four electrons from the outermost orbit of the atom of carbon
The removal of four electrons from the outermost orbit of the atom of carbon will require a large amount of energy.
After the removal of four electrons, there would be only two electrons will remain present in the atom of carbon. While six protons will be left present in the nucleus of the atom of carbon.
In this situation, the presence of six protons in the nucleus and only two electrons in the orbit will make the nucleus of the carbon atom completely unstable. Because it is almost impossible for only two electrons to keep holding the six protons in the nucleus of the carbon atom. Hence, in such a situation the atom of the carbon would be destroyed.
Thus, losing four electrons by the atom of carbon to achieve the stable configuration is not possible.
Situation: (2) Gain of four electrons to the outermost orbit by the atom of carbon.
Achieving the stable electronic configuration by the gain of four electrons by the atom of the element of Carbon
If carbon gains four electrons the number of electrons in the outermost orbit of the atom of carbon will become 10. And the atom of carbon will attain a stable electronic configuration similar to the atom of Neon, a noble gas.
In this way, i.e. by the gain of 4 electrons, the atom of carbon will form C4– ion.
Consequences after the gain of four electrons to the outermost orbit of the atom of carbon
After the gains of four electrons to the outermost orbit, the total number of electrons will become equal to 10 in the atom (ion) of carbon. While the number of protons will remain the same, i.e. equal to six in the nucleus of the atom of the carbon.
In this situation, having 10 electrons in the orbit and only six protons in the nucleus, it will become difficult or almost impossible to keep holding the 10 electrons in the orbit by only six protons present in the nucleus of the atom of carbon.
This situation will also make the atom of carbon unstable and the atom of carbon would be destroyed.
Thus, to achieve the stable electronic configuration, to gain four electrons by the atom of carbon is also not possible.
Formation of Covalent Bond by the Atom of Carbon
Thus, the atom of carbon achieves a stable configuration by the sharing of electrons with the atoms of the same element or the atom(s) of different elements and forms the bond.
The bond formed by the sharing of electrons between two atoms of the same elements or different elements is known as the COVALENT BOND.
Apart from the atoms of carbon many other atoms of elements form bonds by the sharing of electrons. Such bonds are called covalent bonds.
Covalent bond is very much stable.
Carbon forms millions of compounds by the forming of covalent bonds. So far more than ten million carbon compounds are known and still, there is a possibility of millions would be discovered and would be known in the future.
Examples of some compounds formed by the atom of carbon are
Methane (CH4), Ethane (C2H6), Propane (C3H8), Butane (C4H10), Pentane (C5H12), Hexane (C6H14), Heptane (C7H16), Ethylene (C2H4), Acetylene (C2H2), Methanoic Acid (COOH), Ethanoic Acid (CH3COOH), Formaldehyde (CHO), Acetaldehyde (CH3O), etc.