Radiation Flashcards
What is an atom made from?
A nucleus surrounded by electrons. The nucleus contains protons and neutrons.
What are isotopes?
Atoms that have the same number of protons, but different number of neutrons.
Why are the nuclei of some isotopes unstable?
They emit radiation and break down to form smaller nuclei
What do atoms contain?
Three sub-atomic particles called protons, neutrons, and electrons.
Where can you find the protons and neutrons?
In the nucleus at the centre of the atom.
Where are electrons arranged?
In the energy levels, or shells, around the nucleus.
Properties of sub-atomic particles:
Particle Relative mass Relative charge
Proton 1 +1
Neutron 1 0
Electron Almost zero -1
What is the number of electrons in an atom always the same as?
The number of protons, so atoms are electrically neutral overall.
Can atoms lose or gain electrons?
Yes. When they do, they form charged particles called ions.
What happens if an atom loses one or more electrons?
It becomes a positively charged ion.
What happens if an atom gains one or more electrons?
It becomes a negatively charged ion.
What is an atomic number?
The number of protons in the nucleus of an atom is called its atomic number.
What is a mass number?
The total number of protons and neutrons in an atom is called its mass number.
What happens when a radioactive isotope decays?
It forms a different number of protons.
The nuclei of some isotopes are unstable. What happens if they split up or ‘decay’ because of this?
They can split up or ‘decay’ and release radiation.
What happens when an atom emits alpha or beta radiation? Why?
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.
Where does most background radiation come from?
Natural sources
Where does most artificial radiation come from?
Medical examinations, such as x-ray photographs.
Do animals emit radiation?
Yes, all animals emit natural levels of radiation?
Do rocks give off radiation?
Some rocks give off radioactive radon gas.
Do you get radiation in soil and plants?
Radioactive materials from rocks in the ground are absorbed by the soil and hence passed on to plants.
What is fission another word for?
Splitting.
What is nuclear fission?
The process of splitting a nucleus is called nuclear fission.
Why are uranium and plutonium isotopes normally used as the fuel in nuclear reactors?
Their atoms have relatively large nuclei that are easy to split, especially when hit by neutrons.
