Radiation

Question 1

What is an atom made from?

Answer 1

A nucleus surrounded by electrons. The nucleus contains protons and neutrons.

Question 2

What are isotopes?

Answer 2

Atoms that have the same number of protons, but different number of neutrons.

Question 3

Why are the nuclei of some isotopes unstable?

Answer 3

They emit radiation and break down to form smaller nuclei

Question 4

What do atoms contain?

Answer 4

Three sub-atomic particles called protons, neutrons, and electrons.

Question 5

Where can you find the protons and neutrons?

Answer 5

In the nucleus at the centre of the atom.

Question 6

Where are electrons arranged?

Answer 6

In the energy levels, or shells, around the nucleus.

Question 7

Properties of sub-atomic particles:

Answer 7

Particle Relative mass Relative charge
Proton 1 +1
Neutron 1 0
Electron Almost zero -1

Question 8

What is the number of electrons in an atom always the same as?

Answer 8

The number of protons, so atoms are electrically neutral overall.

Question 9

Can atoms lose or gain electrons?

Answer 9

Yes. When they do, they form charged particles called ions.

Question 10

What happens if an atom loses one or more electrons?

Answer 10

It becomes a positively charged ion.

Question 11

What happens if an atom gains one or more electrons?

Answer 11

It becomes a negatively charged ion.

Question 12

What is an atomic number?

Answer 12

The number of protons in the nucleus of an atom is called its atomic number.

Question 13

What is a mass number?

Answer 13

The total number of protons and neutrons in an atom is called its mass number.

Question 14

What happens when a radioactive isotope decays?

Answer 14

It forms a different number of protons.

Question 15

The nuclei of some isotopes are unstable. What happens if they split up or ‘decay’ because of this?

Answer 15

They can split up or ‘decay’ and release radiation.

Question 16

What happens when an atom emits alpha or beta radiation? Why?

Answer 16

Its nucleus changes. It becomes the nucleus of a different element. This is because the number of protons in the nucleus determines which element the atom belongs to.

Question 17

Where does most background radiation come from?

Answer 17

Natural sources

Question 18

Where does most artificial radiation come from?

Answer 18

Medical examinations, such as x-ray photographs.

Question 19

Do animals emit radiation?

Answer 19

Yes, all animals emit natural levels of radiation?

Question 20

Do rocks give off radiation?

Answer 20

Some rocks give off radioactive radon gas.

Question 21

Do you get radiation in soil and plants?

Answer 21

Radioactive materials from rocks in the ground are absorbed by the soil and hence passed on to plants.

Question 22

What is fission another word for?

Answer 22

Splitting.

Question 23

What is nuclear fission?

Answer 23

The process of splitting a nucleus is called nuclear fission.

Question 24

Why are uranium and plutonium isotopes normally used as the fuel in nuclear reactors?

Answer 24

Their atoms have relatively large nuclei that are easy to split, especially when hit by neutrons.

Question 25

What happens when a uranuim-235 or plutonium-239 nucleus is hit by a neutron?

Answer 25

• The nucleus splits into two smaller nuclei, which are radioactive.
• Two or three more neutrons are released
• Some energy is released

Question 26

What does nuclear fusion involve?

Answer 26

Two atomic nuclei joining to make a large nucleus. Energy is released when this happens.

Question 27

What do the sun and other stars use nuclear fusion for?

Answer 27

To release energy.