Chapter 19 - Radioactivity Flashcards
What does a radioactive substance contain which causes it to be radioactive?
An unstable nuclei
How does a radioactive substance become stable?
By emitting radiation
What are the 3 main types of radiation?
Alpha, beta, gamma
What is true about the timing of radioactive decay of a substance?
It is random - Cannot be predicted or influenced
What is most background radiation from?
Radioactive substances occurring naturally in rocks or in space or man-made resources such as nuclear fallout
Name some sources of background radiation
Nuclear fallout, air, medical, ground, food and drink, cosmic
What are isotopes of elements?
Atoms with the same number of protons but different numbers of neutrons
In alpha decay, state what happens to the change in the nucleus, what is the particle emitted and the equation
Nucleus loses 2 protons and neutrons
2 protons and neutrons are emitted as an alpha particle
A A-4 + 4 4
Z Z-2 + 2 2
In beta decay, state what happens to the change in the nucleus, what is the particle emitted and the equation
A neutron in nucleus changes to a proton, An electron is created and emitted instantly
A A 0
Z Z+1 -1
What is true about alpha radiation (range, what can stop it and what it is made up of)
Stopped by paper, 5cm range, each particle has 2 protons and neutrons
What is true about beta radiation (range, what can stop it and what it is made up of)
Stopped by aluminium, 1m range, each particle has fast moving electrons
What is true about gamma radiation (range, what can stop it and what it is made up of)
Stopped by thick lead, unlimited range, consists of EM radiation
What can you use to separate a beam of alpha, beta or gamma radiation?
A magnetic field
State the ionising power of alpha, beta and gamma radiation
Alpha most ionising, then beta, then gamma
What does ionising a cell do?
Damages or kills it
