Atomic Structure Flashcards

1
Q

What is the radius of an atom?

A

1x10^-10 m

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

Charges of the subatomic particles

A

proton= +1
neutron= 0
electron= -1

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

Masses of the subatomic particles

A

proton= 1
neutron= 1
electron= 0

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

What happens to electrons when something absorbs electromagnetic radiation?

A

the electrons are moved to a higher energy level, further from the nucleus

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

What happens to electrons when something emits electromagnetic radiation?

A

the electron drops to a lower energy level, closer to to the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Positive ion

A

when an atom has LOST an electron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Negative ion

A

when an atom has GAINED an electron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What do all atoms of an element have the same of?

A

proton number (atomic number)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Mass Number

A

number of protons and neutrons in a nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Atomic Number

A

Number of protons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Isotopes

A

atoms of an element that have the same number of protons, so are from the same element, but they have a different number of neutrons

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

Plum pudding model

A

the atom is a ball of positive charge with negative electrons embedded in it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Gold Foil Experiment: Results

A

most passed straight through
some were deflected so they must have been repelled by the same charge that the alpha particle carried
the repelling charge must have been heavier than the alpha or it would have passed straight through

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

Gold Foil: Conclusions

A

mass of the atom in in a central, positively charged nucleus
the electrons surround the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Role of Neils Bohr

A

adapted the model by suggesting that electrons orbit the nucleus at set distances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The results of the later experiments

A

the positive charge of the nucleus can be divided into a whole number of smaller particles, each with the same amount of positive charge, commonly known as protons

17
Q

Role of James Chadwick

A

1932
carried out a number of experiments which provided evidence that in the nucleus there was also a particle called the neutron

18
Q

Which type of nuclei, decay, and why?

A

Unstable nuclei give out radiation to become more stable

19
Q

Activity

A

the rate at which something decays

20
Q

What is activity measured in?

A

Becquerels

21
Q

One Becquerel=

A

One decay per second, one count rate per second

22
Q

Count rate

A

the number of decays per second

23
Q

3 types of nuclear decay

A

alpha, beta, gamma

24
Q

Alpha

A
  • 2 protons, 2 neutrons
    -strong ionising power
    -absorbed by a few cm of air/paper
    -can cause damage to living cells
25
Beta
- high-speed electron, ejected from the nucleus which turns into a proton and electron, of which the electron is emitted - reasonable ionising power -absorbed by a few mm of aluminium -can cause damage to cells if absorbed -can penetrate into organs
26
Gamma
- Electromagnetic radiation -poor ionising power -absorbed by many cm of lead/many m of concrete - can pass through cells without being absorbed
27
Radioactive contamination
unwanted presence of materials containing radioactive atoms on other materials
28
Irradiation
The process of exposing an object to nuclear radiation Deliberate/Accidental Does not cause the object to become radioactive
29
Ways of protecting from unwanted radiation
use sources with the lowest activity for the shortest time wear appropriate clothing, e.g. lead apron no handling sources with bare hands
30
Hazards of contamination
Food contaminated with an alpha source would be more hazardous than if it had gamma radiation An area contaminated with alpha would not be dangerous unless it was entered, due to the low penetration of alpha radiation However, if it was contaminated with a source of gamma radiation, this would irradiate people nearby
31
Half-Life
-the time it takes for half the nuclei to decay -time taken for the half-life to fall to 50%
32
Alpha in the nuclear equation
Mass is reduced by 4 The atomic number is reduced by 2
33
Beta in the nuclear equation
mass remains the same the atomic number is increased by 1