Atom and Molecules 1

1. The atomic symbol of silver is —————

• (a) Si

• (b) S

• (c) Au

• (d) Ag

2. A box contains some identical red colour balls labelled as A each weighing 2 g. Another box contains identical blue colored balls, labelled as B, each weighing 5 g. In the combinations AB, AB₂, A₂B and A₂B₃ which is applicable?

• (a) Law of Definite proportion

• (b) Law of multiple proportion

• (c) Law of conservation of mass

• (d) None of the above

3. What is the value of Avogadro’s number?

• (a) 6.02 x 10^-23

• (b) 6.02 x 10²³

• (c) 6.02 x 10^-22

• (d) 6.02 x 10²²

4. What is the chemical formula of sodium carbonate?

• (a) Na₂CO₃

• (b) NaHCO₃

• (c) NaCO₃

• (d) Na₂HCO₃

5. Which of the following is the correct pair of atom and its atomic symbol?

• (a) Sulphur – Su

• (b) Potassium – P

• (c) Phosphorus -P

• (d) Sodium- S

6. How many moles are present in 40 g of He?

• (a) 5 moles

• (b) 20 moles

• (c) 6 moles

• (d) 10 moles

7. Atomic mass of Chlorine is ————– (u)

• (a) 34

• (b) 34.5

• (c) 35

• (d) 35.5

8. 46 gm of sodium is equal to ————-

• (a) 7 moles

• (b) 1.5 moles

• (c) 2 moles

• (d) 1 mole

9. The formula of Ammonium Sulphate is —————–

• (a) NH₄SO₄

• (b) NH₄SO₂

• (c) (NH₄)₂SO₄

• (d) NH₂SO₄

10. The atomic symbol of Iron is —————.

• (a) I

• (b) Fe

• (c) Ir

  
  

• (d) Au