2.7 Types of Radiation

What do all forms of the same element have in common?

The same number of protons.

What is the name given to the number of protons in an atom?

Atomic number.

What is an atom's mass number?

The total number of protons and neutrons in an atom.

What is an isotope of an atom?

An atom of an element that has a different number of neutrons (so a different mass number), but the same number of protons.

Why are some atomic nuclei unstable?

● There is an imbalance between the number of protons and neutrons.
● They contain too much energy.

Why do unstable nuclei give out radiation?

● Unstable nuclei undergo decay to become more stable.
● As they release radiation their stability increases.

What is the name of the process in which an unstable nucleus gives out radiation to become more stable?

Radioactive decay.

State the types of nuclear radiation.

1. Alpha particles
2. Beta particles
3. Gamma rays

What are the constituents of an alpha particle?

● Two protons and two neutrons
● It is the same as a helium nucleus

State the absorption materials for alpha radiation.

* Few centimetres of air.
* Thin sheet of paper.

State the absorption materials for beta radiation.

● 3-5mm of aluminium.

● Several metres of air.

State the absorption materials for gamma radiation.

● Several centimetres of lead.
● A few metres of concrete.

Which type of radiation is most ionising?

Alpha radiation.

Which type of radiation is least ionising?

Gamma radiation.

Which type of radiation is least penetrating?

Alpha radiation.

Which type of radiation is most penetrating?

Gamma radiation.

What is the most harmful type of radiation inside the body?

Alpha- it is the least penetrating and most ionising.

What is the most harmful type of radiation outside the body?

Gamma- it is the most penetrating and least ionising.

State two ways of detecting radiation.

* Gieger Muller tube
* Use the different absorption materials

State any changes to mass or charge that occur due to the emission of a gamma ray.

Both mass and charge remain unchanged.

State any changes to mass or charge that occur due to the emission of a beta particle.

Both mass remains unchanged, charge increases by 1.

State any changes to mass or charge that occur due to the emission of an alpha particle.

Mass decreases by 4 and charge decreases by 2.

Describe the nature of radioactive decay.

● Random.
● Which nuclei decays and when is determined only by chance.
● It is impossible to predict which nuclei will decay and when.

State two techniques that can be used when carrying out experimental work, to combat the random nature of decay.

1) Take repeat readings.
2. Carry the experiment out over a long period of time.

Why is radioactive waste such a problem?

● It remains radioactive for thousands of years.
● It can cause harm to living cells so must be stored appropriately.

Give sources of background radiation.

1. Rocks
2. Cosmic rays from space
3. Food
4. Radon gas
5. Medical

How can we prevent radon gas from entering our houses?

Build houses on top of concrete and keep the house ventilated as air absorbs the alpha emitted by radon gas.

Why are pilots more at risk from cosmic radiation?

Because they fly at a higher altitudes and cosmic radiation comes from space.

Why is ionising radiation dangerous?

Radiation is ionising to cells and causes cancer,=.