Valency and Chemical Formulas MCQs Quiz (30 Questions) for TLT, ECT, PST, JEST Exam | General Science

Valency and Chemical Formulas — MCQs Quiz

Subject: Science (Chemistry)  |  Topic: Valency and Chemical Formulas (30 MCQs)

For TLT, ECT, PST, JEST & All Competitive Exams

Test your understanding of Valency and Chemical Formulas with this interactive 30-MCQ quiz — covering valency values, radicals, and the Criss-Cross Method. Select your answer for each question, then click Submit at the end to instantly see your score.

Instructions: Select one option for each question. After answering all questions, click the Submit button below to see your obtained marks and correct/incorrect answers.

1. What is Valency?

The mass of an atom The combining capacity of an atom The number of neutrons The size of an atom

2. What is the valency of Oxygen?

1 2 3 4

3. What is the chemical formula formed between Hydrogen (valency 1) and Oxygen (valency 2)?

HO H₂O HO₂ H₂O₂

4. What is the valency of the Sulfate radical (SO₄)?

1 2 3 4

5. In the Criss-Cross Method, the valency of one element becomes the:

Charge of the other Subscript of the other Mass of the other Color of the compound

6. What is the valency of Hydrogen?

1 2 3 0

7. What is the valency of Carbon?

2 3 4 1

8. What is the valency of Nitrogen?

2 3 4 1

9. What is the valency of Sodium?

1 2 3 4

10. What is the valency of Calcium?

1 2 3 4

11. What is the valency of Chlorine?

1 2 3 4

12. What is the valency of Aluminum?

1 2 3 4

13. What is the formula of Sodium Chloride (Na valency 1, Cl valency 1)?

Na₂Cl NaCl NaCl₂ Na₂Cl₂

14. What is the formula of Calcium Oxide (Ca valency 2, O valency 2)?

CaO₂ Ca₂O CaO Ca₂O₂

15. What is the formula of Aluminum Oxide (Al valency 3, O valency 2)?

AlO Al₃O₂ Al₂O₃ AlO₃

16. What is the formula of Aluminum Sulfate (Al valency 3, SO₄ valency 2)?

Al₂(SO₄)₃ Al₃(SO₄)₂ AlSO₄ Al(SO₄)₃

17. What is the valency of the Hydroxide radical (OH)?

1 2 3 4

18. What is the valency of the Carbonate radical (CO₃)?

1 2 3 4

19. What is the valency of the Nitrate radical (NO₃)?

1 2 3 4

20. What is the valency of the Ammonium radical (NH₄)?

1 2 3 4

21. When both valencies in the criss-cross method are equal, what happens?

Both subscripts become 1 and are not written The compound cannot form Both subscripts double The elements swap valencies

22. When a radical needs more than one unit in a formula, how is it written?

Without brackets In brackets with the number outside In brackets with the number inside only It cannot be written more than once

23. Which rule generally determines the valency of an element based on outer shell electrons?

Law of Conservation of Mass Octet Rule Newton's Law Ohm's Law

24. What is the formula for Magnesium Chloride (Mg valency 2, Cl valency 1)?

MgCl MgCl₂ Mg₂Cl Mg₂Cl₂

25. What is the formula for Sodium Sulfate (Na valency 1, SO₄ valency 2)?

NaSO₄ Na₂SO₄ Na(SO₄)₂ Na₂(SO₄)₂

26. What is the formula for Ammonium Chloride (NH₄ valency 1, Cl valency 1)?

NH₄Cl (NH₄)₂Cl NH₄Cl₂ (NH₄)Cl₂

27. What is the formula for Calcium Carbonate (Ca valency 2, CO₃ valency 2)?

CaCO₃ Ca₂CO₃ Ca(CO₃)₂ Ca₂(CO₃)₂

28. What is the formula for Aluminum Hydroxide (Al valency 3, OH valency 1)?

AlOH Al(OH)₃ Al₃OH Al(OH)

29. What is the formula for Sodium Nitrate (Na valency 1, NO₃ valency 1)?

NaNO₃ Na₂NO₃ Na(NO₃)₂ Na₂(NO₃)₂

30. Why is Valency important in Chemistry?

It determines the color of a compound It helps write correct chemical formulas of compounds It determines the temperature of a reaction It has no practical use

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