A Level H1 Chemistry Atomic Structure Bonding Quiz

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A-Level Chemistry H1 Quiz - Atomic Structure Bonding

Name: ___________________________
Class: ___________________________
Date: ___________________________
Score: _______ / 40

Duration: 60 minutes
Total Marks: 40
Topic: Atomic Structure Bonding (atomic-structure-bonding)

Instructions:

• Answer all 20 questions.
• Section A: Short structured questions (1–8).
• Section B: Data interpretation and bonding diagrams (9–14).
• Section C: Calculations and extended reasoning (15–20).
• Show all working for calculation questions. Use chemical notation where required.

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Section A: Short Structured Questions (1–8)

1. State what is meant by the term isotope. [1]

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2. Give the number of protons, neutrons and electrons in a neutral atom of $^{40}_{20}\text{Ca}$. [1]

Protons: ______ Neutrons: ______ Electrons: ______

3. Write the full electronic configuration of a chlorine atom, atomic number 17. [1]

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4. State the meaning of the term first ionisation energy. [1]

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5. State the type of bonding present in magnesium oxide, MgO. [1]

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6. Draw a dot-and-cross diagram to show the bonding in the molecule $\text{H}_2\text{O}$. Show only outer shell electrons. [2]

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7. Using VSEPR theory, predict the shape and bond angle of the molecule $\text{BF}_3$. [2]

Shape: __________________ Bond angle: _________

8. State the strongest type of intermolecular force present between $\text{NH}_3$ molecules. [1]

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Section B: Data Interpretation and Bonding Diagrams (9–14)

9. The first five successive ionisation energies of an element E are given below:

Ionisation	1st	2nd	3rd	4th	5th
IE / kJ mol⁻¹	496	4562	6912	9543	13353

Deduce the group of element E in the Periodic Table and explain your reasoning. [3]

Group: ______
Explanation: ___________________________________________________________

10. The diagram below shows the orbital overlap in a molecule of ethene, $\text{C}_2\text{H}_4$.

Image pending generation: diagram for Q10.

State the type of bond formed by the side-by-side overlap of p orbitals in this molecule. [1]

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11. Predict the shape and bond angle of the $\text{SF}_6$ molecule using VSEPR theory. Explain your answer. [3]

Shape: __________________ Bond angle: _________
Explanation: ___________________________________________________________

12. Explain why a $\text{H}_2\text{O}$ molecule is polar whereas a $\text{CO}_2$ molecule is non-polar, despite both containing polar bonds. [3]

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13. The table shows the melting points of four substances.

Substance	$\text{NaCl}$	$\text{I}_2$	$\text{SiO}_2$	$\text{Mg}$
Melting point / °C	801	114	1713	650

Identify the type of structure and bonding for each that accounts for the trend. [4]

$\text{NaCl}$: ________________________
$\text{I}_2$: ________________________
$\text{SiO}_2$: ________________________
$\text{Mg}$: ________________________

14. Deduce the electronic configuration of the $\text{Fe}^{2+}$ ion (atomic number of Fe = 26) using the s, p, d notation. [2]

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Section C: Calculations and Extended Reasoning (15–20)

15. Calculate the relative atomic mass of element X given the following isotopic abundances:
$^{63}\text{X}$: 69.2%, $^{65}\text{X}$: 30.8%. [2]

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16. The successive ionisation energies of element Y show a large jump after the 3rd ionisation. Deduce the number of electrons in the outer shell of Y and state its group. Hence write the formula of its oxide. [3]

Outer shell electrons: ______ Group: ______ Oxide formula: ______

17. A sample of neon contains the isotopes $^{20}\text{Ne}$ (90.5%) and $^{22}\text{Ne}$ (9.5%). Calculate the relative atomic mass of this neon sample to 1 decimal place. [2]

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18. Explain, in terms of electrostatic attractions, why the lattice energy of $\text{MgO}$ is more exothermic than that of $\text{NaF}$. [3]

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19. A molecule of $\text{PCl}_5$ has trigonal bipyramidal shape. State the bond angles in the equatorial and axial positions and explain using VSEPR theory how this minimises repulsion. [4]

Equatorial: _________ Axial: _________
Explanation: ___________________________________________________________

20. A student claims that "$\text{CO}_2$ has a higher boiling point than $\text{H}_2\text{O}$ because it has more electrons." Using your knowledge of intermolecular forces, evaluate this claim. [4]

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A-Level Chemistry H1 Quiz - Atomic Structure Bonding (Answer Key)

Total Marks: 40
Topic: Atomic Structure Bonding

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Section A Answers (1–8)

1. [1 mark]
Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
Teaching note: Same proton number = same element; different nucleon number due to neutron difference.

2. [1 mark]
Protons: 20, Neutrons: 20 (40 − 20), Electrons: 20 (neutral atom).
Marking: 1 mark for all three correct.

3. [1 mark]
$1s^2 2s^2 2p^6 3s^2 3p^5$
Teaching note: Fill orbitals in order; Cl has 17 electrons.

4. [1 mark]
The first ionisation energy is the energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous 1+ ions.
Teaching note: Must mention gaseous state and per mole.

5. [1 mark]
Ionic bonding.
Teaching note: MgO is metal + non-metal → transfer of electrons.

6. [2 marks]
O in centre with two H atoms; O has 6 outer e⁻, each H has 1. Two shared pairs.
Marking: 1 mark for correct shared pairs, 1 mark for showing O with 2 lone pairs.
Common mistake: Forgetting lone pairs on oxygen.

7. [2 marks]
Shape: trigonal planar; Bond angle: 120°.
Teaching note: B has 3 bonding pairs, 0 lone pairs → repulsion equal → 120°.

8. [1 mark]
Hydrogen bonding.
Teaching note: NH₃ has N bonded to H, N is highly electronegative.

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Section B Answers (9–14)

9. [3 marks]
Group: 1
Explanation: Large jump between 1st (496) and 2nd (4562) IE shows only 1 electron in outer shell; after removal, next electron is from stable inner shell.
Marking: 1 for group, 2 for reasoning with reference to jump.

10. [1 mark]
Pi (π) bond.
Teaching note: Side-by-side p orbital overlap forms π bond; sigma from end-on.

11. [3 marks]
Shape: octahedral; Bond angle: 90°.
Explanation: S has 6 bonding pairs, 0 lone pairs → 6 electron domains repel equally → octahedral.
Marking: 1 shape, 1 angle, 1 explanation.

12. [3 marks]
H₂O is bent (104.5°) due to 2 lone pairs, bond dipoles do not cancel → polar. CO₂ is linear (180°), bond dipoles equal and opposite cancel → non-polar.
Marking: 1 for H₂O polarity reason, 1 for CO₂ symmetry, 1 for dipole cancellation.

13. [4 marks]
NaCl: ionic lattice; I₂: simple molecular; SiO₂: giant covalent; Mg: metallic.
Marking: 1 each. Relate to MP: ionic/covalent high, molecular low.

14. [2 marks]
Fe: $1s^2 2s^2 2p^6 3s^2 3p^6 3d^6 4s^2$; Fe²⁺ loses 4s first → $1s^2 2s^2 2p^6 3s^2 3p^6 3d^6$.
Marking: 1 for removal order, 1 for final config.

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Section C Answers (15–20)

15. [2 marks]
$A_r = (63 \times 0.692) + (65 \times 0.308) = 43.596 + 20.02 = 63.616 \approx 63.6$
Working: Multiply mass by decimal abundance, sum.
Answer: 63.6

16. [3 marks]
Outer shell: 3 electrons; Group: 13; Oxide: $Y_2O_3$ (Y is 3+, O is 2−).
Marking: 1+1+1.

17. [2 marks]
$A_r = (20 \times 0.905) + (22 \times 0.095) = 18.1 + 2.09 = 20.19 \approx 20.2$
Answer: 20.2

18. [3 marks]
MgO: Mg²⁺ and O²⁻ (charges ±2); NaF: Na⁺ and F⁻ (±1). Higher charge → stronger electrostatic attraction → more exothermic lattice energy. Also smaller ionic radii in MgO.
Marking: 1 charge compare, 1 attraction link, 1 conclusion.

19. [4 marks]
Equatorial: 120°; Axial: 90°.
Explanation: 5 bonding pairs; 3 equatorial minimise 120° repulsions, 2 axial at 90° to minimise total repulsion (axial-equatorial > equatorial-equatorial).
Marking: 1+1+2.

20. [4 marks]
Claim is false. CO₂ is non-polar, only London forces; H₂O has hydrogen bonding (stronger) → higher BP despite fewer electrons. Evaluate: electron count alone insufficient; intermolecular force type dominates.
Marking: 1 identify error, 1 H-bond in water, 1 CO₂ forces, 1 conclusion.