OCR A-Level Chemistry AS Breadth in chemistry (01), June 2022: Question 2

1 mark Ā· Easy difficulty Ā· Multiple Choice

Identify the correct definition of the term electronegativity from the given options.

Practise this question

Question

Question 2 asks: 'What is the meaning of the term electronegativity?' followed by four multiple-choice options: A 'The ability of an atom to attract the electrons in a covalent bond.', B 'The ability of an atom to gain an electron.', C 'The electrostatic attraction between a negative ion and a positive ion.', and D 'The size of the charge on a negative ion.' An answer box is provided alongside a mark value of 1.
Question text

2 What is the meaning of the term electronegativity?

A The ability of an atom to attract the electrons in a covalent bond.

B The ability of an atom to gain an electron.

C The electrostatic attraction between a negative ion and a positive ion.

D The size of the charge on a negative ion.

Your answer [1]

Mark scheme

Show the mark scheme Mark scheme table row showing question number 2, correct answer A, 1 mark, and assessment objective AO1.1.

2 A 1 AO1.1

How to answer it

OCR Chemistry A • Module 2: Foundations in Chemistry • Multiple Choice

Electronegativity Definition & Periodic Trends

šŸ“‹ What this question tests

This question tests pure recall of essential syllabus terminology (AO1.1): the precise definition of electronegativity as defined by the Pauling scale, and the ability to distinguish it from related concepts like electron affinity and ionic bonding.

Question 2 Analysis

Multiple Choice Question (1 Mark)

āœ… Correct Answer: A

A: "The ability of an atom to attract the electrons in a covalent bond."

Mark Scheme Breakdown:
ā€¢ A gives 1 mark (AO1.1).
ā€¢ This is the exact, standard IUPAC / OCR definition. Both parts are vital: the ability of an atom to attract electrons AND specifying that they are in a covalent bond.

šŸ’” Key Knowledge

  • Electronegativity: A measure of the tendency of an atom to attract a bonding pair of electrons in a covalent bond.
  • The Pauling Scale: Quantifies electronegativity from 0.7 to 4.0. Fluorine (F) is the most electronegative element (assigned 4.0).
  • Periodic Trends:
    • Across a period: Increases due to increased nuclear charge and smaller atomic radius with similar shielding.
    • Down a group: Decreases due to increased shielding and larger atomic radius out-weighing the nuclear charge increase.

āŒ Breakdown of Distractors (Common Traps)

  • Option B: "The ability of an atom to gain an electron."
    This loosely describes electron affinity (or oxidizing ability), not electronegativity. Electron affinity refers to forming gaseous negative ions: X(g) + eā» → Xā»(g).
  • Option C: "The electrostatic attraction between a negative ion and a positive ion."
    This is the fundamental definition of ionic bonding.
  • Option D: "The size of the charge on a negative ion."
    This simply describes ionic charge (e.g. 1−, 2−).

šŸ§  Exam Technique & Examiner Insight

  • Word-for-word memorisation: In written short-answer questions, students routinely lose marks by omitting the phrase "in a covalent bond" or writing "attracts a lone pair". Always state: "attract the bonding electrons in a covalent bond".
  • Elimination Strategy: In multiple-choice questions, spot the keywords immediately. As soon as you see "covalent bond", option A stands out as the only option referencing bonded pairs.
  • Bond Polarity link: Remember that a large difference in electronegativity between bonded atoms leads to a permanent dipole (polar covalent bond) or complete transfer of electrons (ionic bond).

Topics

Module 2: Foundations in chemistry Ā· 2.2 Electrons, bonding and structure

Question and mark scheme from the OCR A-Level Chemistry examination, AS Breadth in chemistry (01), June 2022. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.