Matter & The atom

Question 1

What ttype of particles can matter be made from

Answer 1

Atoms, molecules and ions

Question 2

What is diffussion

Answer 2

-The evidence for the existence of small particles

the movement of particles from areas of high concentration to areas of low concentration

Question 3

Law of conservation of mass / matter

Answer 3

The mass of a closed system will remain constant, regardless of the processess acting inside the system.

matter cannot be created or destroyed although it can be rearranged

for any chemical reactions, mass of reactants must equal mass of prducts

Question 4

What did the greeks discover

Answer 4

First to propose that matter was composed of minute particles

democritus - atomos meaning uncuttable, atom

Question 5

Daltons atomic theory

Answer 5

-all matter is made up of very small particles called atoms
-all atoms are indivisible
-atoms cannote be created or destroyed’

Question 6

What did crookes tube demonstrate

Answer 6

Rays coming from the cathode cast a shadow.

Question 7

connected to the negative electrode

Answer 7

cathode

Question 8

connected to the positive electrode

Answer 8

annode

Question 9

explain vaccuum tubes

Answer 9

-Gas at low press.
-electric current passed through
-radiation came from the end of the tube connected to the cathode
-cathode rays

Question 10

What did dalton discover

Answer 10

• Rays cast shadows, travelled in straight lines
• causes glass to glow (flouresce)
• turns a paddle wheel
• Rays are made of particles

Question 11

What did george stoney do

Answer 11

Named the negative particle electron

Question 12

What did jj thomson do

Answer 12

Discovered the elctron

Question 13

Briefly explain thomsons experiment

Answer 13

Beam of cathode rays througha small hole in the anode

beam passed between two metal plates.
beam could be deflected by electronic plates.

therefore beam is made of negative particles

Question 14

What did thomson use to delflect the elecron

Answer 14

magnetic field from an electromagnet

Question 15

What did thomson calculate

Answer 15

The ratio of charge to mass for the electron

Question 16

Cathode rays

Answer 16

Streams of negatively charged particles called electrons.
They travel in straight lines from the cathode to anode.
Are deflected by electric and magnetic fields
Have sufficient energy to move a small object such as a paddle wheel

Question 17

Thomsons plum pudding model

Answer 17

A sphere of positive charge with negative elesctrons embedded in it at random

Question 18

What was robert milikans experiment called

Answer 18

The oil drop exxperiment

Question 19

What did the oil drop experiment do

Answer 19

Measured the charge on the electron

Question 20

Explain the oil drop experiemny

Answer 20

• X rays ionised air molecules by stripping electrons of their atom.
• Oil droplets picked up these electrons and became negative
• He increased the positive charge until the droplet hovered.
• Took measurement and calculated the charge on the electron.

Question 21

What did ernest rutherford do

Answer 21

Fired alpha particles at a thin gold foil
-Thomsons plum pudding model predicted they would pass through with little defelction

Question 22

What the result of the gold foil experiment

Answer 22

Most passed through undeflected, however some bounced right back

Question 23

Explanation for gold foil experimnt

Answer 23

• Hard dense core of positive matter in the center of each atom. the nucleus
• Atoms are mostly empty space

Question 24

Observations of the gold foil experiment

Answer 24

1. Most alpha particles passed straight through undeflected
   ATOMS ARE MOSTLY EMPTY SPACE
2. Some alpha particles are deflected at large angles
   THE ALPHA PARTICLES ARE REPELLED WHEN THEY ARE NEAR THE NUCLEUS
3. A small number of alpha particles are reflected back along their own paths
   HIT HEAD ON WITH NUCLES OF THE ATOM

Question 25

Who discovered the proton how

Answer 25

Rutherford
continued to bomabrd different element such as nitrogen and oxygen.
Small particles were given off- protons

Question 26

Who discovered the neutron how

Answer 26

James chadwick bombarded beryllium with alpha particles.
small particles were gien off that were neutral and had the same mass as the proton - the neutron.