AS Level Chemistry chapter 3: Chemical bonding MCQs with answers

By Team Megalecture · Updated 4 Nov 2026

154 exam-style questions on Chemical bonding, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.

154 questions · 7 topics · 10 per test

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What chapter 3 covers

Ten Chemical bonding questions with answers

Try each one, then open the answer. These ten stay the same; the test draws new ones every time.

1. Electronegativities: H 2.2, C 2.6, N 3.0, O 3.4, Cl 3.2. Which bond is the most polar?

  1. A
    C–Cl
  2. B
    N–H
  3. C
    C–O
  4. D
    O–H
Show answer

Answer: D. Polarity increases with the electronegativity difference: O–H 1.2, N–H 0.8, C–O 0.8, C–Cl 0.6.

2. Propanone (Mr 58) boils at 56 °C but butane (Mr 58) boils at −1 °C. What is the main reason?

  1. A
    propanone forms hydrogen bonds between its molecules
  2. B
    propanone molecules have a permanent dipole, so permanent dipole–permanent dipole forces act in addition to id-id forces
  3. C
    butane has weaker covalent bonds
  4. D
    propanone has more electrons than butane
Show answer

Answer: B. The polar C=O group gives propanone a permanent dipole. Propanone has no O–H or N–H, so it cannot hydrogen bond with itself; both molecules have the same number of electrons, so id-id forces are similar.

3. What is the shape of the amide ion, NH2−?

  1. A
    non-linear (bent), with a bond angle of about 104.5°
  2. B
    linear, 180°
  3. C
    pyramidal, about 107°
  4. D
    trigonal planar, 120°
Show answer

Answer: A. Nitrogen in NH2− has 5 + 2 + 1 = 8 outer electrons: two bonding pairs and two lone pairs, exactly like water. The shape is therefore bent, with an angle close to 104.5°.

4. Why do the boiling points of the straight-chain alkanes increase from methane to hexane?

  1. A
    larger molecules have more electrons, so the instantaneous dipole–induced dipole forces between them are stronger
  2. B
    the C–C covalent bonds become stronger
  3. C
    larger alkane molecules form hydrogen bonds
  4. D
    larger alkane molecules have permanent dipoles
Show answer

Answer: A. Alkanes are non-polar, so the only intermolecular forces are id-id (London) forces. These grow with the number of electrons and the surface area of contact, so more energy is needed to separate larger molecules. Covalent bonds are not broken on boiling.

5. The F–F bond (bond length 142 pm, bond energy 158 kJ mol−1) is shorter than the Cl–Cl bond (199 pm, 242 kJ mol−1). Which statement is correct?

  1. A
    the F–F bond is shorter and therefore stronger, so fluorine is less reactive than chlorine
  2. B
    the F–F bond is weaker because fluorine atoms have more electron shells than chlorine atoms
  3. C
    bond length and bond energy are unrelated, so neither affects reactivity
  4. D
    the F–F bond is shorter but weaker, which helps to make fluorine more reactive than chlorine
Show answer

Answer: D. Shorter bonds are usually stronger, but F–F is an exception: the small atoms bring their lone pairs close together and they repel. The weak bond gives a low activation energy, so fluorine is very reactive.

6. In the calcium fluoride lattice, each Ca2+ ion is surrounded by eight F− ions. How many Ca2+ ions surround each F− ion?

  1. A
    2
  2. B
    4
  3. C
    8
  4. D
    16
Show answer

Answer: B. There are twice as many F− ions as Ca2+ ions, so each F− must have half as many oppositely charged neighbours: 8 / 2 = 4. Answering 16 multiplies by the ratio instead of dividing.

7. Ionic bonding is best described as

  1. A
    the sharing of a pair of electrons between two atoms
  2. B
    the electrostatic attraction between oppositely charged ions
  3. C
    the attraction between positive ions and delocalised electrons
  4. D
    the attraction between molecules with permanent dipoles
Show answer

Answer: B. Ionic bonding is the electrostatic attraction between cations and anions in a giant lattice. Shared pairs describe covalent bonding; ions plus delocalised electrons describe metallic bonding.

8. Why does ice float on water?

  1. A
    ice has stronger covalent bonds than liquid water
  2. B
    hydrogen bonds hold the molecules in an open lattice in ice, so they are further apart on average than in the liquid
  3. C
    ice contains trapped air
  4. D
    molecules in ice form fewer hydrogen bonds than in liquid water
Show answer

Answer: B. In ice each water molecule is held by four hydrogen bonds in a regular, open hexagonal arrangement. When ice melts some of these break and the molecules pack more closely, so the liquid is denser.

9. How many electrons are shared between the two carbon atoms in a molecule of ethene, C2H4?

  1. A
    2
  2. B
    4
  3. C
    6
  4. D
    8
Show answer

Answer: B. The C=C double bond consists of two shared pairs, so four electrons are shared. Two would be a single bond and six a triple bond.

10. In a dot-and-cross diagram of magnesium oxide, how many electrons are shown in the outer shell of the oxide ion, and how many of these came from magnesium?

  1. A
    6 and 0
  2. B
    8 and 2
  3. C
    8 and 1
  4. D
    10 and 2
Show answer

Answer: B. Oxygen has six outer electrons and gains two from magnesium, so the O2− ion is drawn with eight outer electrons, two of them shown with magnesium's symbol.

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How many Chemical bonding MCQs are there?

154, each with the answer and a short explanation, across 7 topics: Electronegativity and bonding, Ionic bonding, Metallic bonding, Covalent bonding and coordinate (dative covalent) bonding, Shapes of molecules, Intermolecular forces, electronegativity and bond properties, Dot-and-cross diagrams. Every chapter test draws ten of them, so you can take it many times.

Is the AS Level Chemistry chapter 3 test free?

Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.

How is the chapter test marked?

The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.

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