Exercise Solutions Available
Step-by-step answers for all textbook questions in this chapter
Instructions
- Time: 1 hour 30 minutes
- Maximum Marks: 50
- Answer all sections.
Section A — One Mark (10 × 1 = 10 marks)
1. Define sublimation and give one example. 2. What is the atomic number of carbon? 3. State the modern periodic law. 4. What colour does phenolphthalein turn in a base? 5. Name the hardest allotrope of carbon. 6. Write the molecular formula of methane. 7. How many electrons can the first shell (K shell) hold? 8. What is valency? 9. Write the chemical formula of baking soda. 10. Is rusting a physical or chemical change?
Section B — Short Answer (5 × 3 = 15 marks)
Answer any five:
11. Compare the three states of matter in a table. 12. Write the electronic configurations of sodium (Z = 11) and chlorine (Z = 17). What is the valency of each? 13. State two achievements and two limitations of Mendeleev's periodic table. 14. Distinguish between acids and bases with two properties and one example each. 15. Explain catenation and tetravalency in carbon. 16. Explain the pH scale with examples of acidic, neutral, and alkaline substances. 17. Distinguish between saturated and unsaturated hydrocarbons with formulae.
Section C — Long Answer (5 × 5 = 25 marks)
Answer all:
18. (a) Describe the structure of an atom. Explain the three subatomic particles with their charges, masses, and positions. OR (b) Explain the allotropes of carbon. Compare diamond and graphite with diagrams.
19. (a) Explain the modern periodic table. Describe periodic trends in atomic size and metallic character. OR (b) Explain acids, bases, and salts. Describe the neutralisation reaction with two examples. List four common salts and their uses.
20. (a) Explain physical and chemical changes. Give four examples of each and state two differences. OR (b) Describe hydrocarbons — alkanes, alkenes, and alkynes — with general formulae, examples, and uses.
Correction Checklist
- [ ] Formulae written correctly
- [ ] Electronic configurations checked
- [ ] Chemical equations balanced
- [ ] All properties listed with correct examples