Q13
1 markMCQSection A

Assertion (A): Carbon has a strong tendency to either lose or gain electrons to attain noble gas configuration.

Reason (R): Carbon has four electrons in its outermost shell and has the tendency to share electrons with carbon or other elements.

Carbon and its Compounds
Bonding in Carbon – The Covalent Bond

Options

(i)Both (A) and (R) are true and (R) is correct explanation of the assertion (A).
(ii)Both (A) and (R) are true, but (R) is not the correct explanation of the assertion (A).
(iv)(A) is false, but (R) is true.
(iii)(A) is true, but (R) is false.
Official Answer

Assertion (A) is false, but Reason (R) is true.

Assertion is falseReason is truecannot gain or losesharing electronstetravalent

Marking Scheme

  • 1Identify that Assertion (A) is false because carbon cannot easily gain or lose four electrons due to energy and nuclear charge constraints. (0.5 marks)
  • 2Identify that Reason (R) is true because carbon has 4 valence electrons and readily shares them to form covalent bonds. (0.5 marks)

Hint

Consider how difficult it is for a carbon atom with 6 protons to hold 10 electrons or to lose 4 electrons completely.

Quick Oral Answer

Assertion is false because carbon cannot easily form C4+C^{4+} or C4−C^{4-} ions due to high energy requirements and nuclear instability. Reason is true because carbon is tetravalent and shares electrons to achieve stability.

Analysis & Explanation

The Assertion (A) states that carbon has a strong tendency to either lose or gain electrons. This is false. Carbon has an atomic number of 6 with an electronic configuration of 2,42, 4. To attain a noble gas configuration, it would need to either gain 4 electrons (forming C4−C^{4-}) or lose 4 electrons (forming C4+C^{4+}). However, gaining 4 electrons is difficult because a nucleus with 6 protons cannot easily hold 10 electrons, and losing 4 electrons requires an exceptionally large amount of energy. Therefore, carbon does not have a strong tendency to lose or gain electrons; instead, it overcomes this by sharing electrons.


The Reason (R) states that carbon has four electrons in its outermost shell and has the tendency to share electrons. This is true. Carbon is tetravalent and achieves stability by sharing its 4 valence electrons with other carbon atoms or atoms of other elements, forming covalent bonds.


Thus, Assertion (A) is false, but Reason (R) is true.

Common Mistakes

  1. 1Assuming carbon easily forms C4+C^{4+} or C4−C^{4-} ions.
  2. 2Misinterpreting the assertion as true because carbon 'needs' to gain or lose electrons to complete its octet, without considering the physical feasibility of doing so.

Interesting Facts

If carbon were to form ionic bonds by losing 4 electrons, the energy required (sum of first four ionization energies) is so high that no ordinary chemical reaction can provide it!

Spotted a mistake or something unclear?

Tell us — we fix reported answers fast.

Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2020?

This question carries 1 mark in the CBSE Class 10 Science 2020 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Carbon and its Compounds" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Bonding in Carbon – The Covalent Bond" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2020 paper?

This is a MCQ question from Section A in the CBSE Class 10 Science 2020 paper.