krit.club logo

Carbon and its Compounds - Versatile nature of carbon

Grade 10CBSE

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

🔑Concepts

•

Carbon is known for its versatile nature due to two main properties: Catenation and Tetravalency.

•

Catenation: This is the unique ability of carbon atoms to form bonds with other atoms of carbon, giving rise to large molecules. These can be long chains, branched chains, or even ring structures. The C−CC-C bond is very strong and stable.

•

Tetravalency: Carbon has a valency of 44 (1s22s22p21s^2 2s^2 2p^2), meaning it is capable of bonding with four other atoms of carbon or atoms of other monovalent elements like HH, ClCl, etc., or even divalent elements like OO and SS.

•

Small Atomic Size: The small size of the carbon atom allows its nucleus to hold the shared pairs of electrons more strongly, making the covalent bonds extremely stable.

•

Hydrocarbons: Compounds containing only carbon and hydrogen. They are classified into Saturated (C−CC-C single bonds) and Unsaturated (C=CC=C double or C≡CC \equiv C triple bonds).

•

Isomerism: Carbon compounds with the same molecular formula but different structural arrangements are called isomers. This contributes to the vast number of carbon compounds existing in nature.

📐Formulae

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

CnH2n (General formula for Alkenes)C_n H_{2n} \text{ (General formula for Alkenes)}

CnH2n−2 (General formula for Alkynes)C_n H_{2n-2} \text{ (General formula for Alkynes)}

Valency of Carbon=4\text{Valency of Carbon} = 4

💡Examples

Problem 1:

Identify the type of hydrocarbon and the number of hydrogen atoms in a molecule containing 55 carbon atoms that has one double bond.

Solution:

The compound is an Alkene with the formula C5H10C_5H_{10}.

Explanation:

Since the molecule contains a double bond, it is an alkene. Using the general formula CnH2nC_n H_{2n} where n=5n=5: C5H2×5=C5H10C_5 H_{2 \times 5} = C_5 H_{10}. Therefore, there are 1010 hydrogen atoms.

Problem 2:

Why does silicon (SiSi) not show catenation to the same extent as carbon (CC), despite being in the same group?

Solution:

Si−SiSi-Si bonds are weaker compared to C−CC-C bonds because silicon has a larger atomic size.

Explanation:

Carbon is small, allowing the nucleus to hold the shared electron pair strongly in a C−CC-C bond. Silicon atoms are larger, making the Si−SiSi-Si bond longer and significantly weaker, leading to unstable chains compared to carbon.

Problem 3:

Draw the electron dot structure of Ethane (C2H6C_2H_6).

Solution:

Each CC atom shares 11 electron with the other CC atom and 33 electrons with three HH atoms.

Explanation:

In C2H6C_2H_6, two carbon atoms are linked by a single covalent bond (C−CC-C). Each carbon atom then completes its tetravalency by forming single bonds with three hydrogen atoms: H3C−CH3H_3C - CH_3.