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Showing 2 questions in Chemistry for Class 10. Tap a card to reveal the answer.
ChemistryCarbon and its CompoundsmediumWhy does carbon form a very large number of compounds?
Reveal answer ↓
What it is
Carbon forms millions of compounds because it makes four strong covalent bonds and chains (catenation).
Answer
Carbon has four valence electrons, so it shares electrons to form four strong covalent bonds rather than gaining or losing electrons. Two special properties help: catenation (carbon atoms link with other carbon atoms to form long chains, branches and rings) and tetravalency (it can bond with four other atoms such as hydrogen, oxygen, nitrogen). Together these give a huge number of stable compounds.
Carbon valency = 4 (forms 4 covalent bonds)
- •4 valence electrons -> 4 covalent bonds
- •Catenation: C-C chains, branches, rings
- •Tetravalency allows bonding with many elements
- •Small size -> strong stable bonds
Why learn this
It's why all life, fuels, plastics and medicines are carbon-based - the reason 'organic' chemistry exists.
💡 Memory trick
Carbon's superpowers: Tetravalency (4 bonds) + Catenation (C-C chains).
ChemistryCarbon and its CompoundsmediumWhat is a homologous series? State two of its characteristics.
Reveal answer ↓
What it is
A homologous series is a family of carbon compounds with the same general formula, differing by CH2.
Answer
A homologous series is a group of organic compounds having the same general formula and the same functional group, in which each successive member differs from the previous one by a -CH2- unit. Two characteristics are: (1) all members have similar chemical properties because of the same functional group, and (2) their physical properties such as boiling point change gradually as the molecule gets bigger. The alkanes (CH4, C2H6, C3H8, ...) are an example.
Successive members differ by CH2
- •Same general formula and functional group
- •Successive members differ by -CH2-
- •Similar chemical properties; gradual change in physical properties
- •Example: alkanes
Why learn this
It lets chemists predict the properties of thousands of organic compounds from one pattern.
💡 Memory trick
Each member differs by CH2; same functional group, gradually changing physical properties.