Structure of Atom

Question 1

Introduction:

What does the word A-tomio means in greek?

The greek word for Atoms

Answer 1

Uncuttable or non divisible

Question 2

Introduction:

Why did the ideas remained dominant?

Answer 2

The idea of atoms remained domonant because there were only speculations and there was not way to test them experimentaly.

Question 3

Introduction:

Who proposed the first atomic theory of matter?

Daltons atomic Theory

Answer 3

John Dalton in 1803

He is a British school teacher

Question 4

Introduction:

What did Daltons theory regard?

Answer 4

It regarded that atoms are the ultimate particle of matter.

Question 5

Introduction:

What did Dalton’s Atomic theory Explain?

Answer 5

Dalton’s Atomic Theory explained the:
1. Law of Conservation of mass
2. Law of Constant composition
3. Law of Multiple Proportions

Question 6

Introduction:

What did Dalton’s Atomic theory failed to explain?

Answer 6

It failed to explain the Electrical charge

Question 7

Discovery of Sub-Atomic Particles:

________ charges repel each other and ________ attract each other.

Answer 7

Like charges,
Unlike charges

It is like a magnet

Question 8

Discovery of Electrons:

What are cathode ray discharge tube made of?

Answer 8

Cathode ray discharge tube is made of glass with two thin pieces of metals called Electrodes sealed in it

Question 9

Discovery of Electrons:

How can the electrical discharge be seen in the through the glasses?

Answer 9

it can only be seen at low pressure and high voltage

Question 10

Discovery of Electrons:

How was the pressure of the other types of gases adjusted?

Answer 10

Through evacuation of glass tubes

Question 11

Discovery of Electrons:

In which direction does the cathode ray move?

Answer 11

It moves from the negative charge to the positive charge.

Question 12

Discovery of Electrons:

For further verification what is coated behind the anode?

Answer 12

Phosphoresent material Zinc Sulphate

It creates a bright spot when the rays strike it.

Question 13

Discovery of Electrons:

Cathode rays consists of negativly charged particles called?

Answer 13

Electrons

It can be observed in the presence of electric and magnetic field.

Question 14

Charge to mass ratio of Electrons:

Who measured the ratio of electric charge to the mass of electron using a cathode ray tube?

Answer 14

J.J Thomson

1897

Question 15

Charge to mass ratio of Electrons:

The amount of deviation of the particle in the presence of Electric and magnetic field depends upon:

Answer 15

• Magnitude of the negative charge of the particle
• Mass of the particle
• Strength of the electric and magnetic field

Question 16

Charge to mass ratio of Electrons:

The value of Electric charge/Mass of Electrons is:

Answer 16

1.758820 x 10¹¹ C Kg −¹

Question 17

Charge of the electron:

Oil drop experiment determines:

Answer 17

the charge of the Electron

Question 18

Charge of the electron:

Who found the oil drop method?

Answer 18

R.A Millikan

Question 19

Charge of the electron:

Charge of the electron:

Answer 19

-1.6 x 10−¹⁹ C

Question 20

Charge of the electron:

Mass of the electron:

Answer 20

9.1094 x 10−³¹ Kg

Question 21

Discovery of Protons and Neutrons:

THe smallest and lightest positive ion was obtained from Hydrogen and was called as ________.

Answer 21

Protons

Question 22

Discovery of Protons and Neutrons:

Who found Neutrons?

Answer 22

James Chadwick

Question 23

Discovery of Protons and Neutrons:

How did he find that it was protons:

Answer 23

When he found Neutral particles with the mass slightly greater than protons he named it as Neutrons.

Question 24

Thomson Model of atom:

Who proposed the plum pudding model?

Answer 24

J.J Thomson

In 1897

Question 25

Thomson Model of atom:

When did Thomson recieve the Nobel prize?

Answer 25

1906

Question 26

Rutherford’s Nuclear model of Atom:

Radius of the Atom:

Answer 26

10−¹⁰

Question 27

Rutherford’s Nuclear model of Atom:

The radius of the Nucleus:

Answer 27

10−¹⁵

Question 28

Atomic Number and Mass number:

Atomic Number=

Answer 28

• The number of protons inthe nucleus of an atom
• The number of electrons in an atom

Question 29

Atomic Number and Mass number:

Earlier the number of protons and neutrons are collectively called as ___________.

Answer 29

Nucleons