Practice S2.2 The covalent model with authentic IB Chemistry exam questions for both SL and HL students. This question bank mirrors Paper 1A, 1B, 2 structure, covering key topics like atomic structure, chemical reactions, and organic chemistry. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.
Paper
Level
Question 1
SLPaper 2
Carbon is an element with several allotropes, each with distinct physical and electrical properties. Two common forms are diamond and graphite, which have very different uses in technology and industry.
1.[2]
Describe the bonding and structure of diamond in terms of its geometry and bonding type.
2.[2]
Describe the bonding and structure of graphite and how its layers are arranged.
3.[2]
Explain, in terms of electronic structure, why graphite conducts electricity whereas diamond does not.
4.[2]
State one technological use for each allotrope and relate it to a property explained above.
Question 2
SLPaper 2
Hydrogen cyanide () is a toxic gas used in chemical synthesis and historically known for its lethal effects. Understanding its bonding and polarity helps explain its reactivity and behavior in biological systems.
1.[1]
Draw the Lewis (electron dot) structure of , showing all bonds and lone pairs.
2.[1]
Predict the shape of the molecule using VSEPR theory.
3.[2]
Explain whether is a polar molecule, referring to bond polarity and molecular geometry.
4.[1]
Suggest how the polarity of influences its solubility in water.
Question 3
SLPaper 2
Phosphorus trifluoride ( ) is a covalent compound.
1.[1]
Draw the Lewis (electron dot) structure of .
2.[1]
State the number of bonding pairs and lone pairs around the phosphorus atom.
3.[2]
Deduce the molecular geometry (shape) of and predict the approximate bond angle.
4.[2]
Explain why is a polar molecule.
Question 4
SLPaper 2
The structure of urea is shown below.
1.[1]
State the meaning of the term covalent bond.
2.[2]
Identify the number of sigma () and pi () bonds present in a urea molecule.
3.[1]
Deduce the molecular geometry around the carbon atom in urea.
4.[1]
Deduce the molecular geometry around each nitrogen atom in urea.
5.[2]
Predict the approximate bond angles around the carbon atom and explain your answer.
Question 5
SLPaper 1A
Which substance dissolves in water to form a solution that does not conduct electricity?
Question 6
HLPaper 1A
What is the formal charge of the oxygen atom in ?
Question 7
HLPaper 1A
Which species has the longest carbon to oxygen bond length?
Question 8
SLPaper 1A
Which is the correct order based on increasing strength?
Question 9
HLPaper 1A
Which of the following species has a square planar molecular geometry?
Question 10
HLPaper 1A
Which combination correctly describes the geometry of the carbonate ion, ?
| Answer | Electron domain geometry around | Molecular geometry around |
|---|---|---|
| A | Trigonal planar | Trigonal pyramidal |
| B | Tetrahedral | Trigonal planar |
| C | Trigonal planar | Trigonal planar |
| D | Tetrahedral | Trigonal pyramidal |