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Carbon and its Compounds - BONDING IN CARBON – THE CO VALENT BOND

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 has 44 valence electrons in its LL shell.

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To achieve a noble gas configuration, carbon cannot form ionic bonds. Gaining 44 electrons to form C4−C^{4-} is difficult for a nucleus with 66 protons to hold 1010 electrons. Losing 44 electrons to form C4+C^{4+} requires a massive amount of energy.

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Carbon overcomes this by sharing its valence electrons with other atoms. This type of bonding is known as Covalent Bonding.

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A Covalent Bond is formed by the sharing of an electron pair between two atoms so that both atoms can achieve a completely filled outermost shell.

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Types of Covalent Bonds: Single Bond (sharing 11 pair, e.g., H−HH-H), Double Bond (sharing 22 pairs, e.g., O=OO=O), and Triple Bond (sharing 33 pairs, e.g., N≡NN \equiv N).

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Tetravalency: Since carbon has a valency of 44, it is capable of bonding with four other atoms of carbon or atoms of other mono-valent elements.

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Catenation: Carbon has the unique ability to form bonds with other atoms of carbon, giving rise to large molecules. This property is called catenation.

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Covalent compounds have low melting and boiling points because the forces of attraction between the molecules (intermolecular forces) are weak.

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Covalent compounds are generally poor conductors of electricity as the electrons are shared and no charged particles (ions) are formed.

📐Formulae

Z=6  ⟹  K:2,L:4Z = 6 \implies K: 2, L: 4

CH4 (Methane)CH_4 \text{ (Methane)}

C2H6 (Ethane)C_2H_6 \text{ (Ethane)}

O2 (Double Bond: O=O)O_2 \text{ (Double Bond: } O=O)

N2 (Triple Bond: N≡N)N_2 \text{ (Triple Bond: } N \equiv N)

💡Examples

Problem 1:

Explain the formation of a molecule of Water (H2OH_2O) using the concept of covalent bonding.

Solution:

In H2OH_2O, Oxygen (Z=8Z=8) has a configuration of 2,62, 6 and needs 22 electrons. Hydrogen (Z=1Z=1) needs 11 electron. Oxygen shares one electron with each of the two Hydrogen atoms.

Explanation:

Each Hydrogen atom shares its single electron with Oxygen, and Oxygen shares two of its six valence electrons (one with each Hydrogen). This results in two single covalent bonds, allowing Oxygen to reach 88 electrons and Hydrogen to reach 22 electrons (duplet).

Problem 2:

Why does Carbon form compounds mainly by covalent bonding?

Solution:

Carbon has 44 electrons in its outermost shell. To attain noble gas configuration, it would have to either gain or lose 44 electrons. 1. It could gain 44 electrons to form C4−C^{4-}, but it is difficult for the nucleus with 66 protons to hold 1010 electrons. 2. It could lose 44 electrons to form C4+C^{4+}, but it requires a very large amount of energy to remove 44 electrons. Therefore, Carbon shares electrons.

Explanation:

Sharing electrons (Covalent bonding) is energetically more favorable for Carbon than forming ionic bonds.

Problem 3:

Calculate the total number of single covalent bonds in a molecule of Propane (C3H8C_3H_8).

Solution:

C-C bonds: 2C-H bonds: 8Total bonds: 10\begin{array}{r} \text{C-C bonds: } 2 \\ \text{C-H bonds: } 8 \\ \hline \text{Total bonds: } 10 \end{array}

Explanation:

In Propane, the three carbon atoms are linked in a chain by 22 single bonds (C−C−CC-C-C). Each terminal carbon is bonded to 33 hydrogens, and the middle carbon is bonded to 22 hydrogens, totaling 88 C−HC-H bonds. 2+8=102 + 8 = 10.