P4- Atomic Structure

Question 1

Explain the energy levels in a atomic structure.

Answer 1

1. Electrons can move between energy levels.
2. The further an energy level is from the nucleus, the more energy an electron in that energy level has.
3. Electrons can move between energy levels by absorbing or releasing electromagnetic radiation.
4. If an atom loses one or more electron it turns into a positively charged ion.

Question 2

What are isotopes?

Answer 2

Isotopes are different forms of the same element.
- atoms with the same element with the same number of protons but a different number of neutrons.

(Same atomic number but a different mass number)

Question 3

What are the number of protons in an atom called?

Answer 3

Atomic number

Question 4

What does the atomic number of an atom tell you about?

Answer 4

1. The protons in a nucleus give the nucleus it’s positive charge.
2. So the atomic number of an atom tells us about the charge of the nucleus.

Question 5

What is the mass number?

Answer 5

The mass number of an atom is the sum of the number of protons and the number of neutrons.

Question 6

If some isotopes are unstable what does that mean?

Answer 6

1. They emit (give out) radiation from their nuclei to try and become more stable.
2. This process is called radioactive decay.
3. The radiation emitted is called nuclear radiation.

(isotopes that give out nuclear radiation are called radioactive isotopes).

Question 7

What are the four different types of nuclear radiation?

Answer 7

1. Alpha particle.
2. Beta particle.
3. Gamma rays.
4. Neutrons.

Question 8

What is an alpha particle?

Answer 8

2 neutrons and 2 protons.

Question 9

What is a beta particle?

Answer 9

A fast-moving electron.

Question 10

What are gamma rays?

Answer 10

Waves of electromagnetic radiation.

Question 11

What is ionising radiation?

Answer 11

1. Ionising radiation is a radiation that can knock electrons off atoms and turn them into ions.
   (alpha particles, beta particles and gamma rays are types of ionising radiation)

Question 12

What’s the ionising power in alpha particles?

Answer 12

Strong.

Question 13

What is the range in air in an alpha particle?

Answer 13

A few centimetres

Question 14

What is the alpha particles stopped by?

Answer 14

A sheet of paper.

Question 15

What is the ionising power in beta particles?

Answer 15

Moderate

Question 16

What is the range in air in beta particles?

Answer 16

A few meters.

Question 17

What is the beta particles stopped by?

Answer 17

A sheet of aluminium.

Question 18

What is the ionising power for gamma rays?

Answer 18

Weak.

Question 19

What is the range in air in gamma rays?

Answer 19

A long distance.

Question 20

What is the gamma rays stopped by?

Answer 20

Thick sheets of lead or meters of concrete.

Question 21

What is alpha decay?

Answer 21

Alpha decay is when an alpha particle is emitted from a radioactive nucleus.

Question 22

What happens when a nucleus emits an alpha particle?

Answer 22

It atomic number goes down by 2 and it’s mass number gies down by 4.

Question 23

What is beta decay?

Answer 23

Beta decay is when a beta particle is emitted from a radioactive nucleus.

Question 24

What happens during beta decay?

Answer 24

1. A neutron is in the nucleus turns into a proton.
2. This means that the nucleus has one more proton, so it’s atomic number goes up by 1
3. It also means the positive charge of the nucleus increases.

Question 25

What’s the atomic mass of a beta particle?

Answer 25

-1

Question 26

What do gamma rays do?

Answer 26

1. Gamma ways are a way of getting rid of extra energy from a nucleus. 2. When they are emitted, they don’t change the mass or charge of the atom and nucleus. (gamma rays don’t change the charge or mass of the nucleus)

Question 27

What is the activity of a source?

Answer 27

The number of decays per second.

Question 28

How can radioactive decay be measured?

Answer 28

With a Geiger- Muller

Question 29

What are the hazards (dangers) of ionising radiation?

Answer 29

1. Ionising radiation can enter living cells and ionise atoms in them. 2. This can damage the cells, causing cancer or kill cells off completely.

Question 30

What is the exposure to radiation called?

Answer 30

Irradiation. - irradiated objects don’t become radioactive themselves.

Question 31

What can you do to stop irradiation from happening?

Answer 31

1. Store radioactive sources in lead-lined boxes when they are not being used. 2. Stand behind barriers that will absorb radiation when using sources. 3. Keep sources as far away from you as possible. (Eg. Hold it arm length)

Question 32

What is contamination?

Answer 32

Contamination is radioactive particles getting onto objects. (if unwanted radioactive atoms get onto or into a object, it is contaminated)

Question 33

If unwanted radioactive atoms get into or onto objects what can happens?

Answer 33

1. These contaminating atoms might then decay and release radiation which could harm you. 2. Being contaminated by a source may cause more damage than if you are irradiated by the same source , as you may carry it for a long time.

Question 34

What should you do to help stop contamination?

Answer 34

1. You should wear gloves. 2.use tongs when handling radioactive sources.

Question 35

Inside the body, what sources are the most dangerous to be contaminated by and why?

Answer 35

1. Inside the body, alpha sources are the most dangerous to be contaminated by. 2. This is because alpha particles are the most ionising type of radiation.

Question 36

Inside the body, what sources are the least dangerous to be contaminated by and why?

Answer 36

1. Inside the body, beta particles and gamma rays are less damaging 2. Because they are less ionising.

Question 37

Why are Gamma sources the least dangerous inside the body?

Answer 37

1. Because Gamma rays are the least ionising type of radiation 2. And they mostly pass straight out without doing any damage.

Question 38

Outside the body, what sources are the least dangerous to be contaminated by and why?

Answer 38

1. Alpha particles are the least dangerous outside the cell to be contaminated by 2. This is because alpha particles can’t get through the skin and damage your organs.