Electron Discovery

Q.

Mass of an electron is approximately 1837 times that of a proton.

1. True

2. False

Q.

Which one is slightly heavier? Proton or neutron?

Q.

The mass of an atom is the sum of the masses of protons and neutrons.

1. True

2. False

Q. Match the sub-atomic particles with the scientists who discovered them:

1. J.J. Thomson
2. E. Goldstein
3. J. Chadwick

Q.

State the mass of neutron in gram and atomic mass unit.

Q.

The mass of an electron is negligible when compared to that of a proton.

1. True

2. False

Q.

___ discovered the electron and ___ proposed its name.

1. Goldstein, Chadwick

2. Stoney, Farday

3. Thompson, Stoney

4. Faraday, Thompson

Q.

What are orbits and why are they called stationary orbits?

Q.

Assertion: When we rub a comb in dry hair, then this comb attracts small pieces of paper.
Reason : The comb gets an electric charge that varies with the number of charged particles within the atoms present in the comb.

1. Atoms are not divided

2. Atoms are divisible

3. Atoms repel each other

4. Atoms can attract each other

Q.

On what basis did Bohr assume the concept of the stationary orbit of an atom?

Q.

If we rub a comb in dry hair, it attracts small pieces of paper. Which of the following statements can be related to this?

1. Atoms repel each other

2. Atoms can attract each other

3. Atoms are divisible

4. Atoms are not divided

Q.

The mass of the neutron is less than that of an electron.

1. True
2. False

Q.

From what device are we able to atomic or the sub-atomic particles

Q. What is the observation of discovery of electron

Q.

who discovered electrons?

Q.

1. As long as an electron revolves in a particular orbit the electron does not lose its energy, therefore, these orbits are called stationary orbits and the electrons are said to be in stationary energy states.
2. Each orbit or shell is associated with a definite amount of energy hence these are also called energy levels.
3. An electron jumps from a lower energy level to a higher energy level by absorbing energy. it jumps from a higher energy level to a lower energy level by emitting energy in the form of electromagnetic radiation.
4. Electrons move around the nucleus in specified circular paths called orbits or shell or energy levels and are designated as K, L, M, and N respectively

Arrange the above Bohrs postulates theory in the correct sequence.

1. 4, 1, 3, 2

2. 4, 2, 1, 3

3. 4, 1, 2, 3

4. 2, 4, 1, 3

Q. Electronswere discovered by:

1. J. J. Thomson’s
2. William Crooks
3. E. Goldstein
4. Rutherford

Q. Describe Bohr’s stable orbit atomic model.

Q. The first model of an atom was proposed by

1. Niels Bohr
2. James Chadwick
3. Ernest Rutherford
4. J.J Thomson

Q. Electrons were discovered by _______ .

1. Rutherford
2. E.Goldstein
3. Chadwick
4. J.J Thomson

Q.

In the plum pudding model which of the following subatomic particles was not included?

1. Neutron

2. Proton

3. Electron

4. Both proton & neutron

Q.

What are the cathode rays constituted of?

1. neutrons

2. electrons

3. positively charged alpha particles

4. protons

Q.

Electrons are _____ particles.

1. neutral

2. positively charged

3. negatively charged

4. infinitely charged

Q.

Name the scientist who first measured the e/m ratio of an electron.

1. Rutherford

2. James Chadwick

3. Dalton

4. J. J Thomson