S2.2 The covalent model (HL)
14 revision questions with answers for S2.2 The covalent model (HL). Read them here, or play the set as a class game on the projector. Free to host, and students join with a code.
Molecular geometry of SF₆?
- Trigonal bipyramidal
- Square planar
- OctahedralRight answer
- Square pyramidal
What this set covers
Covalent bonding at HL: molecular shapes with five or six electron domains such as SF₆, PCl₅, XeF₄ and SF₄, hybridisation, sigma and pi bonds, formal charge, resonance and bond order in carbonate and benzene.
- Common mix-up
- Students often mix up sigma and pi bonds: sigma bonds form by head-on overlap and pi bonds by sideways overlap of p orbitals, so ethyne has three sigma and two pi.
- Revision tip
- For ethene, ethyne and NH₃, name the hybridisation and the bond count aloud, then check that you can justify each from the electron domains.
All 14 questions and answers
Molecular geometry of SF₆?
Answer: Octahedral
Molecular geometry of PCl₅?
Answer: Trigonal bipyramidal
Molecular geometry of XeF₄?
Answer: Square planar
Molecular geometry of SF₄?
Answer: Seesaw
Hybridisation of each carbon in ethene?
Answer: sp²
Hybridisation of each carbon in ethyne?
Answer: sp
Hybridisation of nitrogen in NH₃?
Answer: sp³
Covalent bond formed by sideways overlap of p orbitals?
Answer: Pi bond
Numbers of sigma and pi bonds in ethyne, H–C≡C–H?
Answer: 3 σ, 2 π
Formal charge on nitrogen in NH₄⁺?
Answer: +1
The preferred Lewis structure has formal charges…?
Answer: Closest to zero
Describing a molecule by two or more Lewis structures with delocalised electrons?
Answer: Resonance
Bond order of each C–O bond in CO₃²⁻?
Answer: 1.33
Delocalisation in benzene makes all six carbon–carbon bonds…?
Answer: Equal in length
Play it as a class game
Play this set opens it in splycr, where you can host it for your class straight away. Hosting needs no account: put the room code on the projector, and students join from a phone with the code and their first name. Each question plays as multiple choice, and the three wrong options were written for that question.