Topic 5 - Radioactivity

What are the names of the three sub-atomic particles?

Proton, neutron and electron.

What are the charges of:

1. Protons

2. Neutrons

3. Electrons

1. Protons are positive

2. Neutrons are neutral (no charge)

3. Electrons are negative

What is the atomic number?

The number of protons in the atom.

What is the mass number?

The number of protons plus the number of neutrons.

What is an isotope?

An element that has the same number of protons but different number or neutrons.

Why are some elements radioactive?

Their nucleus is unstable.

What can cause an unstable nucleus?

1. unequal number of protons and neutrons

2. large mass number

What is radioactive decay?

The emission of radiation in order to become more stable.

What are the three types of radiation?

alpha, beta, and gamma.

What are the compositions of:

1. Alpha

2. Beta

3. Gamma

1. Alpha is the same as a helium nucleus (2 protons, 2 neutrons)

2. Beta is high-energy electron

3. Gamma is an electromagnetic wave.

What are the materials that can absorb alpha, beta and gamma?

1. Alpha - absorbed by paper

2. Beta - absorbed by 3mm of aluminium

3. Gamma - absorbed by lead, concrete, steel.

Which type of radiation is the most ionising?

Alpha.

Which type of radiation is the least ionising?

Gamma.

Why does radioactive waste from a nuclear power station need to be stored in concrete?

it emits gamma radiation which is very penetrative.

What is background radiation?

Low level radiation that is around us at all times.

How does background radiation vary?

It can vary due to its location and time of year.

Name some natural sources of radiation.

radon gas, rocks, cosmic rays, human body, and food.

Name some artificial sources of radiation.

medical uses, nuclear power.

Where is radon gas from?

The rocks in the ground.

Why do radon levels vary?

Because the type of rock present in a location can vary.

What instrument is used to measure radiation?

Geiger Counter (CPM, CPS, BQ)

How can radon levels be reduced in the home?

Increasing ventilation and floor insulation.