ATOMS, MOLECULES AND IONS

Question 1

Who discovered electrons i.e cathode rays

Answer 1

William Crooke

Question 2

In William crooke’s experiment, the rays were observed as

Answer 2

Streaks of purple light which are attracted to the positive plate of the electric field

Question 3

Cathode rays can be deflected by both electric and magnetic field, true or false

Answer 3

True

Question 4

William Crooke’s experiment in a discharge tube was based on gases at ….

Answer 4

Low pressure

Question 5

The electrodes in the sealed tube were connected to a direct current source of…. Which were

Answer 5

High voltage , lead acid accumulators in series

Question 6

William Crooke observed cathode rays in the year

Answer 6

1870

Question 7

William Crooke’s experiment was based on the …. Nature of electrons

Answer 7

Qualitative

Question 8

Who calculated the charge to mass ratio of electrons

Answer 8

J.J Thompson

Question 9

J.J Thompson’ s experiment was carried out using …. And is considered

Answer 9

Modified cathode ray tube

Quantitative

Question 10

The value of the charge to mass ratio is

Answer 10

1.76 X 10^11 C/Kg

Question 11

J.J Thompson’s aluminium plates were separated about …. Centimetres

Answer 11

5

Question 12

The flourescent screen in Thompson’s experiment was

Answer 12

Zinc sulphide

Question 13

Cathode rays were attracted to

Answer 13

The positive plate

Question 14

In Thompson’s experiment, the magnetic field is equal to

Answer 14

The centripetal force and electric field

Question 15

The formula for charge to mass ratio is

Answer 15

E/rB^2

Question 16

The proton is about … Heavier than an electron

Answer 16

1850 times

Question 17

The absolute charge on an electron was measured by …. In the year….

Answer 17

R.Millikan in 1909

Question 18

J.J measured charge to mass ratio in the year

Answer 18

1897

Question 19

R. Millikan balance gravitational force with

Answer 19

Electric force

Question 20

By R. Millikan’s experiment, the value of charge on an electron is calc to be

Answer 20

1.6 ×10^-19

Question 21

Who discovered proton

Answer 21

Goldstein

Question 22

When was proton discovered

Answer 22

1886

Question 23

Goldstein used a…… To observe the motion of protons

Answer 23

A modified cathode ray tube

Question 24

Protons were observed as

Answer 24

Luminous rays passing through perforations in the cathode and attracted too the negative plate

Question 25

Protons were named by

Answer 25

Ernest Rutherford

Question 26

Rutherford's Model of the atomic structure was called

Answer 26

The nuclear model

Question 27

The alpha scattering experiment is also known as.... And lead to a definition of the correct. .

Answer 27

Gold foil experiment, atomic structure

Question 28

In their experiments in .....German scientist Boethe and student, Becker bombarded

Answer 28

In 1930 Berrylium with alpha particles

Question 29

Who discovered neutrons?

Answer 29

James Chadwick

Question 30

Nothing

Answer 30

Nothjng

Question 31

James Chadwick was the first to correctly name the emissions from various existing experiments in

Answer 31

1932

Question 32

The gold foil experiment was carried out in.... By ....

Answer 32

1911 by Ernest Rutherford, Hans Giegar and Ernest Mardsen

Question 33

Who discovered x-rays when?

Answer 33

Konrad Röentgen in 1896

Question 34

Mosley's experiment was to determine

Answer 34

The absolute number of protons and neutrons in the nucleus

Question 35

The formula v^1/2 = Z(c-b) is the result of

Answer 35

Mosley's experiment where v is frequency and c and b are constants

Question 36

Neutrons have ... Charge and are ... By electric and magnetic fields

Answer 36

No charge, undeflected

Question 37

Mass of neutron and proton on the carbon-12 scales are

Answer 37

1.0087 and 1.0073

Question 38

Formula for binding energy is

Answer 38

dM/A × 1.492×10^-10 J

Question 39

For electrovalent bond, ionisation energy must be ...., Lattice energy and electron affinity must be. .

Answer 39

Low and large; high

Question 40

In a mass spectrometer the function of the ion detector is to ....

Answer 40

Convert mass to charge ratio to electric current

Question 41

The lighter the mass, the smaller the . . . And..... the deflection

Answer 41

Radius, larger

Question 42

The energy required to break down a nucleus to its components is called

Answer 42

Binding energy exp in joule per nucleus

Question 43

Who suggested the quantisation theory

Answer 43

Max Planck

Question 44

Niel Bohrs theory states that

Answer 44

Electrons exist in quantum energy levels