p4 Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

who came up with the plum pudding model?

A
  • JJ Thompson
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

describe the plum pudding model

A
  • an atom with a ball of positive charge surrounded by electrons (which carry a negative charge)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

which two scientists conducted the alpha-scattering experiment?

A
  • Marsden and Rutherford
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

describe the alpha-scattering experiment

A
  1. Scientists took a piece of gold foil
  2. Scientists then fired POSITIVE alpha particles at the gold
    - Most of the alpha particles passed straight through = so most of the atom is EMPTY SPACE.
    - Sometimes, the alpha particles bounce straight back = the centre of the atom contains the MOST MASS.
    - Some deflected slightly = the CENTRE OF THE ATOM HAS A POSITIVE CHARGE.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what did Bohr discover?

A
  • electrons orbit the nucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what did James Chadwick discover?

A
  • the nucleus contains neutrons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

in which order were protons, neutrons and electrons discovered?

A
  • electrons, protons and neutrons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
  • describe the nuclear model of the atom
A
  • The model has a very small positively charged nucleus surrounded by outer electrons at a large distance from the nucleus. The protons and neutrons, which contain nearly all of the mass of the atom, are located in the nucleus at the centre of the atom.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the radius of an atom?

A
  • 1 x 10^-10 m
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the radius of a nucleus?

A
  • 1 x 10^-14 m
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what kind of process is radioactive decay?

A
  • random
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the units of radioactivity?

A
  • Becquerels (Bq)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what piece of equipment is used to measure radioactive decay?

A

gieger counter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is an alpha particle?

A
  • helium nucleus (2 protons and 2 neutrons)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the range of an alpha particle in the air?

A
  • a few cm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are beta particles?

A
  • fast-moving electrons (e-1)
17
Q

what is the range of a beta particle in the air?

A
  • a few metres
18
Q

what are gamma rays?

A
  • an electromagnetic wave
19
Q

what is the range of a gamma ray in the air?

A
  • several metres
20
Q

what can an alpha particle be stopped by?

A
  • stopped by a sheet of paper
21
Q

what can a beta particle be stopped by?

A
  • stopped by a thin sheet of aluminium
22
Q

what can a gamma ray be stopped by?

A
  • concrete or a thick block of lead
23
Q

what is the ionising power of an alpha particle?

A
  • very strong
24
Q

what is the ionising power of a beta particle?

A
  • quite strong
25
Q

what is the ionising power of a gamma ray?

A
  • weak
26
Q

what is meant by the term a half-life?

A
  • the amount of time it takes for a nuclei to divide
27
Q

what is irradiation?

A
  • the process by which an object is exposed to radiation.
28
Q

what is ionising radiation?

A
  • the radiation emitted from unstable nuclei
29
Q

what precautions should people take when working with radioactive isotopes?

A
  • wear a lead apron
  • use a lead glass screen
  • use a radiation monitor to see how much radiation a person receives
30
Q

what is radioactive contamination?

A
  • when unwanted radioactive isotopes end up on other materials.
31
Q

what is the nuclear equation of a beta particle?

A
  • mass number does not change
  • atomic number increases by 1
32
Q

what is the nuclear equation of an alpha particle?

A
  • mass number decreases by 4
  • atomic number decreases by 2
33
Q

what is the nuclear equation of a gamma ray?

A
  • the mass and atomic number do not change in gamma radiation