Intermolecular forces, electronegativity and bond properties
Cambridge A-Level Chemistry (9701) · Unit 3: Chemical bonding · 6 flashcards
Intermolecular forces, electronegativity and bond properties is topic 3.6 in the Cambridge A-Level Chemistry (9701) syllabus , positioned in Unit 3 — Chemical bonding , alongside Electronegativity and bonding, Ionic bonding and Metallic bonding. In one line: Electronegativity is the measure of the ability of an atom in a chemical compound to attract electrons in a covalent bond. The Pauling scale is commonly used, with fluorine being the most electronegative element.
Marked as AS Level: examined at AS Level in Paper 1 (Multiple Choice), Paper 2 (AS Structured Questions) and Paper 3 (Advanced Practical Skills). The same content may also be assumed in Paper 4 (A Level Structured Questions).
The deck below contains 6 flashcards — 4 definitions and 2 key concepts — covering the precise wording mark schemes reward. Use the 4 definition cards to lock down command-word answers (define, state), then move on to the concept and calculation cards to handle explain, describe, calculate and compare questions.
Electronegativity
Electronegativity is the measure of the ability of an atom in a chemical compound to attract electrons in a covalent bond. The Pauling scale is commonly used, with fluorine being the most electronegative element.
What the Cambridge 9701 syllabus says
2025-2027 syllabus, in our words · AS LevelWhat the syllabus expects you to be able to do in this topic, in plain English. For the exact wording, see the official syllabus (PDF).
- (a) Describe hydrogen bonding, only for molecules with N-H or O-H groups; water and ammonia serve as simple examples. (b) Explain, through hydrogen bonding, the anomalous behaviour of H₂O as ice and water: its fairly high boiling and melting points, its fairly high surface tension, and how dense solid ice is compared with liquid water.
- Use electronegativity to explain why bonds are polar and why molecules have dipole moments.
- (a) Describe what van der Waals' forces are: intermolecular forces acting between molecular entities that are not caused by bond formation. Use the term as a general label for every kind of intermolecular force. (b) Describe the two types: id-id (instantaneous dipole-induced dipole) forces, which are also known as London dispersion forces, and pd-pd (permanent dipole-permanent dipole) forces, a type that includes hydrogen bonding. (c) Describe hydrogen bonding, which you should understand as a particular kind of pd-pd force between molecules, occurring where hydrogen is bonded to an atom of high electronegativity.
- State that ionic, covalent and metallic bonds are, in general, stronger than intermolecular forces.
Cambridge syllabus keywords to use in your answers
These are the official Cambridge 9701 terms tagged to this section. Mark schemes credit responses that use the exact term — weave them into your answers verbatim rather than paraphrasing.
Tips to avoid common mistakes in Intermolecular forces, electronegativity and bond properties
- › Remember that a water molecule can form four hydrogen bonds: two through its lone pairs and two through its hydrogen atoms.
Define electronegativity.
Electronegativity is the measure of the ability of an atom in a chemical compound to attract electrons in a covalent bond. The Pauling scale is commonly used, with fluorine being the most electronegative element.
Explain how electronegativity differences lead to bond polarity.
When there's a significant electronegativity difference between two bonded atoms, the more electronegative atom attracts electron density, resulting in a partial negative charge (δ-) and the other atom a partial positive charge (δ+). This creates a polar covalent bond.
What is a dipole moment?
A dipole moment is a measure of the polarity of a molecule. It arises when there is an uneven distribution of electron density, creating a separation of charge. It's a vector quantity with both magnitude and direction.
How can a molecule with polar bonds be nonpolar overall?
If the individual bond dipoles within a molecule cancel each other out due to the molecule's symmetry, the overall dipole moment is zero, and the molecule is nonpolar. CO₂ is an example, despite having polar C=O bonds.
List the relative strengths of ionic, covalent, metallic bonding, and intermolecular forces.
Ionic, covalent and metallic bonds are all strong, with strengths that overlap widely, so there is no fixed order between them; many covalent bonds (for example C–C in diamond) are as strong as ionic or metallic bonding. All three are much stronger than intermolecular forces. Among intermolecular forces: hydrogen bonds > permanent dipole-dipole forces > instantaneous dipole-induced dipole forces (for molecules of similar size).
Give examples of compounds with each of the following: ionic, covalent, and metallic bonding.
Ionic: NaCl (sodium chloride). Covalent: CH₄ (methane). Metallic: Fe (iron).
More Chemistry flashcards
Browse every 9701 flashcard topic by syllabus area.
All Chemistry FlashcardsMore topics in Unit 3 — Chemical bonding
Intermolecular forces, electronegativity and bond properties sits alongside these A-Level Chemistry decks in the same syllabus unit. Each uses the same spaced-repetition system, so progress in one informs the next.
Key terms covered in this Intermolecular forces, electronegativity and bond properties deck
Every term below is defined in the flashcards above. Use the list as a quick recall test before your exam — if you can't define one of these in your own words, flip back to that card.
How to study this Intermolecular forces, electronegativity and bond properties deck
Start in Study Mode, attempt each card before flipping, then rate Hard, Okay or Easy. Cards you rate Hard come back within a day; cards you rate Easy push out to weeks. Your progress is saved in your browser, so come back daily for 5–10 minute reviews until every card reads Mastered.
Study Mode
Rate each card Hard, Okay, or Easy after flipping.