1. Which of the following statements is not true about an atom?

2. The molecule having an atomicity of 4 is:

3. The molecule having an atomicity of 4 is:

4. The chemical symbol for sodium is

5. What is the formula mass unit of ZnO?

6. Percentage of calcium in calcium carbonate is

7. The atomic mass of sodium is 23. The number of moles in 46g of sodium is ________.

8. A change in the physical state can be brought about

9. Which of the following has maximum number of atoms?

10. 3.42 g of sucrose are dissolved in 18 g of water in a beaker. The number of oxygen atoms in the solution are

11. 1 u or 1 amu means

12. How many times an atom of sulphur is heavier than an atom of carbon?

13. Which of the following would weigh the highest?

14. The chemical symbol for nitrogen gas is

15. Which has maximum number of molecules?

16. The molecular formula of potassium nitrate is ________.

17. The molecular formula of potassium nitrate is ________.

18. Which of the following correctly represents 360 g of water?
(i) 2 moles of H₂O
(ii) 20 moles of water
(iii) 6.022 × 10²³ molecules of water
(iv) 1.2044 × 10²⁵ molecules of water

19. Which of the following represents a correct chemical formula?

20. How many atoms of oxygen are present in 300 grams of CaCO₃?