Q1. [1]
Assertion (A) : Carbon shares its valence electrons with other atoms of carbon or with atoms of other elements.
Reason (R) : The shared electrons belong to the outermost shells of both the atoms and lead to both atoms attaining the noble gas configuration.
- A Both, Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- B Both, Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
- C Assertion (A) is true, but Reason (R) is false.
- D Assertion (A) is false, but Reason (R) is true.
Previously asked in CBSE board exam
2026 31/1/1 Q24
Generated by claude-sonnet-4-6 · 2026-06-15 06:46 · grounding rag
Model Answer
Option A — Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A). Carbon forms covalent bonds by sharing valence electrons; these shared electrons count towards both atoms, helping each achieve a noble gas configuration.
Explanation
- The Assertion is correct: carbon shares its 4 valence electrons with other carbon atoms or other elements (covalent bonding).
- The Reason is also correct and directly explains the Assertion: in covalent bonding, the shared pair belongs to the outermost shell of both atoms, allowing each to attain a completely filled outermost shell (noble gas configuration).
- Since R logically explains why A occurs, the answer is A, not B.
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