Q1
1 markVery Short AnswerSection A

How are covalent bonds formed?

Carbon and its Compounds
Bonding in Carbon – The Covalent Bond
Official Answer

Covalent bonds are formed by the sharing of valence electrons (or electron pairs) between two atoms. This sharing allows both participating atoms to attain a stable, completely filled outermost shell (noble gas configuration).

sharing of electronsvalence electronsnoble gas configurationoutermost shell

Marking Scheme

  • 1Mentioning the sharing of valence electrons/electron pairs between two atoms (0.5 marks)
  • 2Stating the purpose: to attain a stable noble gas configuration / completely filled outer shell (0.5 marks)

Hint

Think about how atoms achieve a stable noble gas configuration without completely transferring electrons.

Quick Oral Answer

Covalent bonds are formed when two atoms share their valence electrons to complete their outermost shells and achieve a stable noble gas configuration.

Analysis & Explanation

According to the NCERT textbook, elements achieve stability by attaining a noble gas configuration. Carbon has 4 electrons in its outermost shell and cannot easily gain or lose 4 electrons due to energy constraints. It overcomes this by sharing its valence electrons with other atoms. The bonds formed by such sharing of electron pairs between two atoms are called covalent bonds.

Common Mistakes

  1. 1Confusing covalent bonds with ionic bonds (which involve complete transfer of electrons).
  2. 2Forgetting to mention that only valence electrons participate in sharing.

Interesting Facts

The simplest covalent molecule is Hydrogen (H2\text{H}_2), where two hydrogen atoms share one pair of electrons to achieve the stable electronic configuration of Helium.

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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 Very Short Answer question from Section A in the CBSE Class 10 Science 2020 paper.