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Carbon and its Compounds - Covalent bonding in carbon compounds

Grade 10CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Carbon has an atomic number of 66 with an electronic configuration of 2,42, 4. It needs 44 more electrons to attain the stable noble gas configuration of Neon (2,82, 8).

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Carbon cannot form ionic bonds easily because removing 44 electrons to form C4+C^{4+} requires a huge amount of energy, and gaining 44 electrons to form C4−C^{4-} is difficult for a nucleus with 66 protons to hold 1010 electrons.

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Carbon overcomes this problem by sharing its valence electrons with other atoms of carbon or with atoms of other elements. This sharing of electrons results in the formation of covalent bonds.

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Tetravalency: Since carbon has 44 valence electrons, it is capable of bonding with four other atoms of carbon or atoms of some other mono-valent elements like Hydrogen (HH), Chlorine (ClCl), etc.

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Catenation: Carbon has the unique ability to form bonds with other atoms of carbon, giving rise to large molecules with long chains, branched chains, or even rings.

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Physical Properties: Covalent compounds generally have low melting and boiling points because the intermolecular forces are weak. They are also poor conductors of electricity as no ions or charged particles are formed.

📐Formulae

C=1s22s22p2 or (2,4)C = 1s^2 2s^2 2p^2 \text{ or } (2, 4)

CH4 (Methane - simplest hydrocarbon)CH_4 \text{ (Methane - simplest hydrocarbon)}

C2H6 (Ethane)C_2H_6 \text{ (Ethane)}

CO2 (Carbon Dioxide)CO_2 \text{ (Carbon Dioxide)}

CnH2n+2 (General formula for Alkanes)C_nH_{2n+2} \text{ (General formula for Alkanes)}

💡Examples

Problem 1:

Explain why Carbon forms covalent bonds and not ionic bonds.

Solution:

Carbon has 44 electrons in its outermost shell. To form an ionic bond, it must either lose 44 electrons to form C4+C^{4+} or gain 44 electrons to form C4−C^{4-}. Losing 44 electrons requires a very high amount of energy, and the C4−C^{4-} ion would be highly unstable as 66 protons cannot easily hold 1010 electrons. Therefore, Carbon shares electrons to form covalent bonds.

Explanation:

This addresses the energy constraints and nuclear stability issues associated with the C4+C^{4+} and C4−C^{4-} ions.

Problem 2:

Describe the bonding in a Nitrogen molecule (N2N_2).

Solution:

Nitrogen has an atomic number of 77 and an electronic configuration of 2,52, 5. To attain an octet, each Nitrogen atom shares 33 electrons with the other Nitrogen atom.

Explanation:

This sharing of three pairs of electrons results in a triple covalent bond (N≡NN \equiv N) between the two atoms.

Problem 3:

Draw the electron dot structure of Methane (CH4CH_4).

Solution:

Carbon is at the center with 44 valence electrons. Four Hydrogen atoms, each with 11 valence electron, surround the Carbon. Carbon shares one electron with each Hydrogen atom.

Explanation:

By sharing, Carbon achieves an octet (88 electrons) and each Hydrogen achieves a duplet (22 electrons), forming four single covalent bonds.

Covalent bonding in carbon compounds Revision - Class 10 Science CBSE