History of the atom

Question 1

who explained the properties of matter?

Answer 1

john Dalton

Question 2

what did john dalton do

Answer 2

explained the properties of matter

Question 3

what did william crooks do

Answer 3

discovered cathode rays and proved they moved from the cathode towards the anode

Question 4

who discovered cathode rays and proved they moved from the cathode towards the anode

Answer 4

William crooks

Question 5

what did JJ Thomson do

Answer 5

used cathode rays to show the existence of electrons
calculated the charged to mass ratio (e/m)
proposed the plum pudding model

Question 6

who used cathode rays to show the existence of electrons
calculated the charged to mass ratio (e/m)
proposed the plum pudding model

Answer 6

JJ Thomson

Question 7

what did robert millikan do

Answer 7

measured the charge on an electron using the oil drop experiment

Question 8

who measured the charge on an electron using the oil drop experiment

Answer 8

Robert Millikan

Question 9

what did ernest rutherford do

Answer 9

discovered the nucleus, proved it was positively charged due to protons
atoms are made up of mainly empty space

Question 10

who discovered the nucleus, proved it was positively charged due to protons
atoms are made up of mainly empty space

Answer 10

Ernest Rutherford

Question 11

who discovered the neutron?

Answer 11

James Chadwick

Question 12

what did james chadwick do

Answer 12

discovered the neutron

Question 13

what is daltons atomic theory

Answer 13

all matter is composed of small particles called atoms
all atoms are indivisible

Question 14

what is the evidence for daltons atomic theory

Answer 14

ammonia reacts with hydrochloric acid to form ammonium chloride in a tube

Question 15

describe the procedure of daltons experiment

Answer 15

a piece of ammonia soaked cotton wool is placed at one end of a glass tube
a piece of HCl acid soaked cotton wool is placed at the other end of the tube
stopper is put on both ends
after a few minutes a white substance is formed - ammonium chloride

Question 16

explain the procedure of dalton’s experiment

Answer 16

ammonium and HCl acid evaporate from the cotton wool and the gas particles diffuse throughout the glass tube
when ammonia particles collide with the HCl acid particles they react to form ammonium chloride

Question 17

Relative charge of a proton

Answer 17

+1

Question 18

Relative charge of an e-

Answer 18

-1

Question 19

Relative charge of a neutron

Answer 19

0

Question 20

relative mass of a proton

Answer 20

1

Question 21

relative mass of a neutron

Answer 21

1

Question 22

relative mass of an e-

Answer 22

negligable

Question 23

location of a proton

Answer 23

nucleus

Question 24

location of a neutron

Answer 24

nucleus

Question 25

location of an e-

Answer 25

orbitals

Question 26

cathode

Answer 26

negative

Question 27

anode

Answer 27

positive

Question 28

draw the diagram for Dalton’s atomic theory

Question 29

describe the maltese cross experiment

Answer 29

metal plate attached to end of cathode emits radiation
cathode rays cause glass tube to flouresce green
maltese cross is placed at end of vacuum tube and a shadow was cast.

Question 30

what did the maltese cross experiment prove

Answer 30

something is emitted from the cathode and moved in straight lines

Question 31

what did the paddle wheel show in the maltese cross experiment

Answer 31

the paddle turned away from the cathode proving cathode rays were coming from the cathode

Question 32

describe jj thomsons experiment

Answer 32

cathode ray tube with a high voltage applied to a metal filament causing charged particles to the emitted from the surface of the metal
particles are attracted to anode which has a hole
particles pass through and move towards the charged parallel plates
particles attracted to positively charged plates and hit a florescent screen

Question 33

what did jj thomson experiment prove?

Answer 33

the particles were negatively charged

Question 34

how did jj thomson calculate the ratio of the charge on an e- to the mass (e/m)

Answer 34

using at electromagnet

Question 35

properties of cathode rays

Answer 35

travel in straight lines
negatively charged

Question 36

describe thomsons plum pudding model

Answer 36

an atom is a sphere of positive charge
electrons are randomly embedded in the sphere

Question 37

how did thomson account for a neutral atom?

Answer 37

using the plum pudding model- equal amount of negative and positive charges

Question 38

describe Robert millikans experiment

Answer 38

oil droplet sprayed between 2 charged metal plates
xrays used to ionise air between plates
oil droplet picks up electrons as it travels through ionised air and becomes negatively charged

Question 39

describe rutherfords experiment

Answer 39

alpha particles are fired at a thin piece of gold foil
flourescent screen is placed around experiment

Question 40

describe the results of rutherfords experiment

Answer 40

some were deflected at large angles- positive nucleus repels positive alpha particles when they pass close by

most alpha particles passed through as atoms are mainly empty space

some were reflected backwards along the same path- alpha particles collided with dense nucleus that contains most of the mass of an atom

Question 41

describe chadwicks experiement

Answer 41

bombarded a piece of beryllium with alpha particles and found that particles containing no charge came from beryllium.
he found that neutral particles knocked protons out of paraffin wax therefore they have the same mass as protons