R4RIN – MCQs, Mock Tests | CBES Board Class 9 STRUCTURE OF ATOMS MCQS CLASS 9

If n = 3 we are in

1. K shell
2. L shell
3. M shell
4. F shell

✅ Correct Answer: 3

Water that contains H-2 atoms is called

1. heavy water
2. light water
3. pure water
4. chlorinated water

✅ Correct Answer: 1

Electron revolves around the nucleus in orbits which have

1. variable energy
2. fixed energy
3. infinite energy
4. zero energy

✅ Correct Answer: 2

In Rutherfords experiment ? particles were deflected because of

1. electrostatic repulsion between ? particles and positively charged part of atom
2. electrostatic repulsion between ? particles and positively charged part of atom
3. electrostatic repulsion between ? particles and positively charged part of atom
4. electrostatic attraction between ? particles and positively charged part of atom

✅ Correct Answer: 1

The energy of an electron in orbit is proportional to

1. distance between shells
2. distance from nucleus
3. distance between two nuclei
4. positive charge inside nucleus

✅ Correct Answer: 2

According to Rutherford most of the space occupied by the atom is

1. filled
2. partially filled
3. empty
4. none of above

✅ Correct Answer: 3

The electronic configuration is the arrangement of electrons in

1. nucleus
2. shells
3. sub-shells
4. all of above

✅ Correct Answer: 3

Electrons revolve only in those orbits with angular momentum as an

1. half integral multiple of h
2. integral multiple of h
3. integral multiple of h ? 2?
4. half integral multiple of 2?

✅ Correct Answer: 3

After 3s the sub-shell begin to fill is

1. 3p
2. 3d
3. 3f
4. 4s

✅ Correct Answer: 1

When an electron jumps from lower orbit to higher orbit

1. light is emitted
2. electrons are emitted
3. electrons are absorbed
4. light is absorbed

✅ Correct Answer: 4

The lowest energy orbital among the following is

1. 3h
2. 2p
3. 3s
4. 3p

✅ Correct Answer: 1

When Uranium-238 emits ? particles it decays in to

1. Helium
2. Carbon
3. Thorium-234
4. Uranium-235

✅ Correct Answer: 3

D sub-shell can accommodate maximum

1. 2 electrons
2. 10 electrons
3. 14 electrons
4. 6 electrons

✅ Correct Answer: 2

Chlorine-35 exists in nature about

1. 0.35
2. 0.4
3. 0.5
4. 0.75

✅ Correct Answer: 4

Protium has

1. one neutron
2. two neutrons
3. no neutron
4. 3 neutrons

✅ Correct Answer: 3

? particles are

1. positively charged
2. doubly positively charged
3. negatively charged
4. doubly negatively charged

✅ Correct Answer: 2

The energy of emitted light is equal to

1. sum of energy levels
2. difference between energies of orbits
3. product of energies of orbits
4. none of above

✅ Correct Answer: 2

Atoms having same atomic number but different atomic mass are called

1. derivatives
2. isotopes
3. elements
4. isomers

✅ Correct Answer: 2

Rutherford bombarded thin gold foil with

1. ? particles
2. ? particles
3. ? particles
4. neutrons

✅ Correct Answer: 1

Iodine-123 is used to

1. diagnose thyroid problem
2. image the brain
3. kill cancer cells
4. trace the blood flow

✅ Correct Answer: 2