1. Who discovered the electron?
A) Rutherford
B) Chadwick
C) Bohr
D) J.J. Thomson
**Answer: D**
2. Who discovered the nucleus?
A) Dalton
B) Bohr
C) Thomson
D) Rutherford
**Answer: D**
3. Which particle has no charge?
A) Proton
B) Electron
C) Positron
D) Neutron
**Answer: D**
4. Atomic number is equal to:
A) Number of neutrons
B) Protons + Neutrons
C) Number of electrons only
D) Number of protons
**Answer: D**
5. Mass number is equal to:
A) Protons × Neutrons
B) Electrons + Protons
C) Electrons + Neutrons
D) Protons + Neutrons
**Answer: D**
6. Charge of an electron is:
A) +1
B) 0
C) +2
D) –1
**Answer: D**
7. Protons are present in the:
A) Orbit
B) Shell
C) Valence shell
D) Nucleus
**Answer: D**
8. Electron was discovered using:
A) Gold foil experiment
B) Oil drop experiment
C) Alpha scattering experiment
D) Cathode ray tube experiment
**Answer: D**
9. Maximum electrons in K shell are:
A) 8
B) 18
C) 32
D) 2
**Answer: D**
10. Formula for maximum electrons in a shell is:
A) n²
B) 2n
C) n³
D) 2n²
**Answer: D**
11. Maximum electrons in L shell are:
A) 2
B) 18
C) 32
D) 8
**Answer: D**
12. Maximum electrons in M shell are:
A) 8
B) 32
C) 50
D) 18
**Answer: D**
13. Who proposed fixed electron orbits?
A) Dalton
B) Thomson
C) Rutherford
D) Bohr
**Answer: D**
14. Atomic number of Hydrogen is:
A) 2
B) 3
C) 4
D) 1
**Answer: D**
15. Atomic number of Oxygen is:
A) 6
B) 7
C) 9
D) 8
**Answer: D**
16. Carbon has how many protons?
A) 4
B) 8
C) 12
D) 6
**Answer: D**
17. Identity of an element depends on:
A) Electrons
B) Neutrons
C) Mass number
D) Protons
**Answer: D**
18. Isotopes have the same:
A) Mass number
B) Atomic mass
C) Number of neutrons
D) Atomic number
**Answer: D**
19. Isobars have the same:
A) Atomic number
B) Electrons
C) Protons
D) Mass number
**Answer: D**
20. Which particle has negligible mass?
A) Proton
B) Neutron
C) Alpha particle
D) Electron
**Answer: D**
21. Alpha particles are:
A) Electrons
B) Neutrons
C) Protons
D) Helium nuclei
**Answer: D**
22. Rutherford's experiment proved:
A) Atoms are solid
B) Electrons are positive
C) Neutrons exist
D) Atoms have a nucleus
**Answer: D**
23. Most of the atom is:
A) Solid
B) Water
C) Gas
D) Empty space
**Answer: D**
24. Atomic number of Sodium is:
A) 10
B) 12
C) 13
D) 11
**Answer: D**
25. Electronic configuration of Sodium is:
A) 2,7,2
B) 2,8,2
C) 2,6,3
D) 2,8,1
**Answer: D**
26. Atomic number of Chlorine is:
A) 16
B) 18
C) 19
D) 17
**Answer: D**
27. Electronic configuration of Chlorine is:
A) 2,8,8
B) 2,7,8
C) 2,6,9
D) 2,8,7
**Answer: D**
28. Valence electrons are present in the:
A) First shell
B) Inner shell
C) Nucleus
D) Outermost shell
**Answer: D**
29. Noble gases have:
A) Incomplete outer shell
B) One electron
C) Two protons
D) Complete outer shell
**Answer: D**
30. Helium has how many electrons?
A) 1
B) 4
C) 8
D) 2
**Answer: D**
31. Atomic number of Magnesium is:
A) 10
B) 14
C) 16
D) 12
**Answer: D**
32. Electronic configuration of Magnesium is:
A) 2,8,1
B) 2,7,3
C) 2,6,4
D) 2,8,2
**Answer: D**
33. Who discovered the neutron?
A) Rutherford
B) Thomson
C) Bohr
D) Chadwick
**Answer: D**
34. Atomic mass is measured in:
A) kg
B) g
C) mole
D) amu (u)
**Answer: D**
35. One atomic mass unit is:
A) Mass of proton
B) Mass of neutron
C) Mass of electron
D) 1/12 of the mass of Carbon-12 atom
**Answer: D**
36. Calcium has how many shells?
A) 2
B) 3
C) 5
D) 4
**Answer: D**
37. Electronic configuration of Calcium is:
A) 2,8,7,3
B) 2,8,9,1
C) 2,8,6,4
D) 2,8,8,2
**Answer: D**
38. Which particle is negatively charged?
A) Proton
B) Neutron
C) Alpha particle
D) Electron
**Answer: D**
39. Which particle is positively charged?
A) Electron
B) Neutron
C) Photon
D) Proton
**Answer: D**
40. An atom is electrically neutral because:
A) Protons = Neutrons
B) Neutrons = Electrons
C) Mass = Charge
D) Protons = Electrons
**Answer: D**
41. Rutherford used which metal foil?
A) Copper
B) Silver
C) Iron
D) Gold
**Answer: D**
42. Electrons revolve around the:
A) Proton
B) Neutron
C) Alpha particle
D) Nucleus
**Answer: D**
43. Hydrogen-1 has how many neutrons?
A) 1
B) 2
C) 3
D) 0
**Answer: D**
44. The lightest element is:
A) Helium
B) Lithium
C) Carbon
D) Hydrogen
**Answer: D**
45. Oxygen has how many protons?
A) 6
B) 10
C) 16
D) 8
**Answer: D**
46. A neutral Oxygen atom has how many electrons?
A) 6
B) 10
C) 16
D) 8
**Answer: D**
47. Electronic configuration of Oxygen is:
A) 2,8
B) 2,5
C) 2,7
D) 2,6
**Answer: D**
48. The shell nearest to the nuc
leus is:
A) L shell
B) M shell
C) N shell
D) K shell
**Answer: D**
49. The first shell of an atom is called:
A) L shell
B) M shell
C) N shell
D) K shell
**Answer: D**
50. Who proposed the Plum Pudding Model?
A) Bohr
B) Rutherford
C) Dalton
D) J.J. Thomson
**Answer: D**
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