Hybridisation and molecular shape (VSEPR): Class 11 practice
Count the electron domains around the central atom (bond pairs + lone pairs). Read the method, follow the three worked examples, then try the six questions.
What you should know first
- Lewis structures
The idea behind hybridisation and molecular shape (vsepr)
Count the electron domains around the central atom (bond pairs + lone pairs). 2 → sp (linear), 3 → sp² (trigonal planar), 4 → sp³ (tetrahedral). Lone pairs change the shape name: NH₃ pyramidal, H₂O bent.
Step-by-step method
- Count bonded atoms and lone pairs on the central atom.
- Domains → hybridisation.
- Remove lone pairs to name the shape.
Worked example 1 (Basic)
Give the hybridisation and shape of C₂H₄ (each C).
- Bond pairs 3, lone pairs 0 → 3 domains
- Hybridisation sp²; shape trigonal planar
- Answer: sp², trigonal planar
Worked example 2 (Standard)
Give the hybridisation and shape of NH₄⁺.
- Bond pairs 4, lone pairs 0 → 4 domains
- Hybridisation sp³; shape tetrahedral
- Answer: sp³, tetrahedral
Worked example 3 (Challenge)
Give the hybridisation and shape of BF₃.
- Bond pairs 3, lone pairs 0 → 3 domains
- Hybridisation sp²; shape trigonal planar
- Answer: sp², trigonal planar
Common mistakes and misconceptions
- Ignoring lone pairs
- Counting a double bond as two domains
Practice questions
- (Basic) Give the hybridisation and shape of HCN (C).
- (Basic) Give the hybridisation and shape of SO₂.
- (Standard) Give the hybridisation and shape of H₃O⁺.
- (Standard) Give the hybridisation and shape of BeCl₂.
- (Challenge) Give the hybridisation and shape of H₂O.
- (Challenge) Give the hybridisation and shape of NH₃.
Answer key with full working
- Q1: Bond pairs 2, lone pairs 0 → 2 domains → Hybridisation sp; shape linear → Answer: sp, linear
- Q2: Bond pairs 2, lone pairs 1 → 3 domains → Hybridisation sp²; shape bent → Answer: sp², bent
- Q3: Bond pairs 3, lone pairs 1 → 4 domains → Hybridisation sp³; shape trigonal pyramidal → Answer: sp³, trigonal pyramidal
- Q4: Bond pairs 2, lone pairs 0 → 2 domains → Hybridisation sp; shape linear → Answer: sp, linear
- Q5: Bond pairs 2, lone pairs 2 → 4 domains → Hybridisation sp³; shape bent → Answer: sp³, bent
- Q6: Bond pairs 3, lone pairs 1 → 4 domains → Hybridisation sp³; shape trigonal pyramidal → Answer: sp³, trigonal pyramidal
Syllabus note
This skill is listed under "Chemical Bonding" for Class 11 in the NCERT/CBSE books. ICSE, IGCSE, IB and state boards may teach it in a different chapter or year.
Answers on this page are generated and automatically re-checked by a second, independent calculation. They have not been reviewed by a teacher — if you spot a problem, tell us on WhatsApp.
Related practice and notes
Frequently asked questions
Which chapter is hybridisation and molecular shape (vsepr) in?
"Chemical Bonding", Class 11 Chemistry (NCERT/CBSE). Other boards may place it differently.
How were the answers checked?
Answers on this page are generated and automatically re-checked by a second, independent calculation. They have not been reviewed by a teacher — if you spot a problem, tell us on WhatsApp.