Atoms and Molecules-Class IX-Vasu Classes


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Atoms and Molecules-Class IX-Vasu Classes

1. Number of which particle differ in Isotopes

a) Positron
b) Electron
c) Neutron
d) Proton

2. How many moles are there in 54gm of water?

a) 6
b) 54
c) 3
d) 18

3. Valency of element X is 3 and valency of element Y is 2. What will be the fromula of the compound fromed?

a) XY3
b) X3Y2
c) X4Y2
d) X2Y3

4. What is the molecular mass of SO2

a) 64 amu
b) 82
c) 100 amu
d) 32amu

5. Christmas pudding model of atom was proposed by

a) Neil Bohr
b) James Chadwick
c) Rutherford
d) Sir J.J. Thomson

6. The particle whose mass is equal to the mass of two protons and two neutrons

a) Beta particle
b) Helium atom
c) Nitrogen atom
d) Alpha particle

7. Name the subatomic particles whose relative charge is zero

a) electron
b) proton
c) nucleus
d) neutron

8. Which one is the heaviest particle among the following?

a) proton
b) alpha particle
c) neutron
d) electron

9. The number of moles in 20gm of water will be

a) 3
b) 1.11
c) 2
d) 2.11

10. one u stands for

a) 12 times the mass of one carbon-12 atom
b) 1/24th mass of One carbon atom
c) 1/12 times the mass of one carbon atom
d) 24 times the mass of one carbon atom

11. Ne , Na+ and F- have same number of

a) Electrons
b) Neutrons
c) Protons
d) Nucleons

12. Which of the following pair has same electronic configuration

a) Cl- ,Ne
b) Na+ , Ar
c) Na+ , Ca2+
d) Cl- , Ar

13. Which radi isotope is used to detect disorder of thyroid gland?

a) Co-60
b) Arsenic-74
c) Iron-59
d) Iodine-131

14. Which of the following are isotopes?

a) mass no-37 , atomic number17
b) atomic number-18 ,mass no.-40
c) atomic number-17 , mass number-35
d) mass no-40 , atomic number -18

15. Anode rays have pure protons when one of these gas is taken

a) Helium
b) Hydrogen
c) Nitrogen
d) Oxygen

16. Which of the following is not a postulate of Dalton's atomic theory?

a) Number of atoms in a comound is fixed
b) Atoms of different elements differ in mass
c) Atoms do not combine in whole numbers
d) Atoms of the same element are identical in all respects
e) Atom is indivisible

17. Whole mass of atom is concentrated at the centre is associated with

a) a very few alpha particles hit back on their path
b) as most of the alpha particles went straight on their path
c) Few alpha particles deflected from their path
d) None

18. What is the mass of 0.5mole of Nitrogen?

a) 28gm
b) 14gm
c) 56gm
d) 27gm

19. What is the formula of aluminium sulphate?

a) Al SO4
b) Al2 (SO4)3
c) Al2(SO4)4
d) Al3 SO4

20. An element X forms an oxide XO.The formula of iits chloride will be

a) X3Cl2
b) XCl
c) X2Cl
d) XCl2

21. If the number of electrons in the M shell of an element are 3 then its atomic number will be

a) 25
b) 15
c) 13
d) 23

22. The idea of fixed energy levels in an atom was given by

a) J.J thomson
b) Rutherford
c) Neils Bohr
d) Goldstein

23. Atomic numbers of elements are X-2 , Y-18 , Z-12 which of these are inert

a) X and Z
b) X and Y
c) X only
d) Y and Z

24. Isotopes of which element are used in a nuclear reactor?

a) Hydrogen
b) Cobalt
c) Carbon
d) Uranium

25. Which of the following rays are used for diagnostic purposes?

a) X-rays
b) Anode rays
c) cathode rays
d) Beta rays

26. Which of the following are isobars

a) Na ,C
b) K , S
c) Cl-35 , Cl-37
d) Ca ,Ar

27. Which of the following is not true for a symbol

a) Represents one mole
b) represent one mole molecule
c) represents one atom
d) represents N atoms

28. What is the atomic number of Mg2+

a) 14
b) 10
c) 22
d) 12

29. Atomicity of Sulphur is

a) 6
b) 5
c) 8
d) 2

30. The outer most shells of elements X and Y have two and six electrons respectively. If X and Y combine the formula of the compound formed will be

a) XY
b) X2Y
c) X2Y3
d) XY2

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