IB myp 4-5 Chemistry – Practice Questions- All Topics
Topic :Periodic Table-Periodic trend group and periods
Topic :Periodic Table- Weightage : 21 %
All Questions for Topic : Metals and Non metals,Transition metals,Noble gases,Periodic trend groups and periods
Question (8 marks) – Solar Energy Chemistry
Solar panels are an alternative to fossil fuels. Silicon (Si) is used in 95% of panels sold today. Elements like gallium (Ga), arsenic (As) and tellurium (Te) are also used in advanced solar panels.
a (2 marks)
Criterion A
Complete the periodic table information for gallium (Ga) and arsenic (As):
| Property | Ga | As |
|---|---|---|
| Group | 3 | |
| Period | 4 |
▶️ Show Answer
Completed Table:
| Property | Ga | As |
|---|---|---|
| Group | 3 | 15 |
| Period | 4 | 4 |
Periodic Table Explanation:
Gallium (Ga):
- Group: 13 (formerly IIIA)
- Period: 4
- Atomic Number: 31
- Uses: Gallium arsenide (GaAs) solar cells
Arsenic (As):
- Group: 15 (formerly VA)
- Period: 4
- Atomic Number: 33
- Uses: Semiconductor dopant in solar cells
Periodic Trends:
Both elements are p-block metals in Period 4, demonstrating how elements in the same period can have different properties but similar applications in solar technology.
b (2 marks)
Criterion A
Explain why solar power is environmentally preferable to fossil fuels.
▶️ Show Answer
Key Advantages:
- Zero operational emissions: No greenhouse gases or air pollutants during electricity generation
- Renewable source: Sunlight is virtually inexhaustible compared to finite fossil fuels
Environmental Impact Comparison:
| Factor | Solar Power | Fossil Fuels |
|---|---|---|
| CO₂ Emissions | ~40g CO₂/kWh (manufacturing only) | 500-1000g CO₂/kWh |
| Air Pollution | None | SO₂, NOx, particulates |
| Water Usage | Minimal | High (cooling, extraction) |
Syllabus Connection:
Relates to The Atmosphere → Emission and environmental implications and demonstrates understanding of sustainable energy solutions.
c (1 mark)
Criterion A
Identify the correct alcohol structure from the options below:
Option A
Option B
Option C
▶️ Show Answer
Answer: Option B (CH₃-CH₂-OH)
Functional Group Analysis:
| Option | Structure | Classification |
|---|---|---|
| A | CH₃-O-CH₃ | Ether (not alcohol) |
| B | CH₃-CH₂-OH | Alcohol (ethanol) |
| C | CH₃-COOH | Carboxylic acid |
Key Identification:
Alcohols are characterized by the presence of a hydroxyl (-OH) group attached to a carbon atom. In Option B, the -OH group is clearly visible at the end of the carbon chain.
d (3 marks)
Criterion A
Explain why carbon and silicon form compounds with similar formulas (e.g., CH₄ and SiH₄).
▶️ Show Answer
Key Reasons:
- Both are in Group 14 of the periodic table
- Have 4 valence electrons (ns²np² configuration)
- Can form 4 covalent bonds to complete their octet
Chemical Bonding Analysis:
Carbon (C):
- Atomic number: 6
- Electron config: 1s² 2s² 2p²
- Forms strong covalent bonds
- Example: Methane (CH₄)
Silicon (Si):
- Atomic number: 14
- Electron config: [Ne] 3s² 3p²
- Forms weaker bonds than carbon
- Example: Silane (SiH₄)
Tetrahedral Structure Comparison
Methane (CH₄)
Silane (SiH₄)
Syllabus Connection:
Demonstrates understanding of Periodic Table → Groups and periods and Bonding → Structure and bonding through comparative analysis of group trends.