Quick answer: Molecular shape follows VSEPR theory: electron domains around the central atom repel and spread as far apart as possible, with lone pairs repelling more than bonding pairs. This Chemistry 11-12 test on VSEPR theory has 8 questions worth 20 marks, to do in 45 minutes: shape of beryllium chloride, water compared with methane and a non-polar molecule with polar bonds. The mark scheme is on a separate page; free printable PDF.
This chemistry grades 11-12 test on VSEPR theory test works like a real class test. The mark scheme is on a separate page, so revise with the lesson first.
This test covers VSEPR shapes, bond angles, electronegativity and polarity. Answer every question, justify explanations with lone pairs or symmetry, and show any working. The total is 20 marks.
Level: Chemistry grades 11-12 (A Level · IB · Class 11-12) · Curriculum: IB S2.2
VSEPR theory test: the test questions
Question 1 Shape of beryllium chloride (2 marks)
Gaseous BeCl₂ has two bonding pairs and no lone pairs on beryllium. Name its shape and state the Cl–Be–Cl angle. (2 marks)Question 2 Water compared with methane (3 marks)
The H–O–H angle in water is 104.5° but the H–C–H angle in methane is 109.5°. Explain the difference. (3 marks)Question 3 A non-polar molecule with polar bonds (3 marks)
The diagram shows CX₄.Question 4 Bond polarity (2 marks)
Electronegativities: H 2.2, C 2.6, O 3.4, F 4.0. Calculate the difference for C–H, C–O and C–F and put the bonds in order of increasing polarity. (2 marks)Question 5 Ammonium and ammonia (3 marks)
Compare the shape and bond angle of NH₄⁺ with those of NH₃. (3 marks)Question 6 Sulfur dioxide polarity (2 marks)
Sulfur dioxide has a bent shape. State and explain whether it is polar. (2 marks)Question 7 Hydrogen iodide (2 marks)
Electronegativities: H 2.2, I 2.7. State which atom carries δ+ in H–I and give the difference in electronegativity. (2 marks)Question 8 Boron trifluoride and ammonia (3 marks)
Both BF₃ and NH₃ contain three polar bonds. Explain why BF₃ is non-polar but NH₃ is polar. (3 marks)
