Radioactivity Flashcards
What is an Isotope?
An atom with a different mass number but the same atomic number. There can be many isotopes of an atom, each with a different number of neutrons.
What happens when more neutrons are added to an atom?
The nucleus gets bigger
What happens when the nucleus gets too big?
The repulsion of the protons can overcome the strong nuclear force, causing some particles to split away from the nucleus of the atom.
What is nuclear decay?
When an atom releases a huge amount of energy in the form of alpha, beta particles or gamma radiation
What are radioisotopes?
Isotopes that undergo nuclear decay
What does alpha decay cause?
Causes the nucleus to eject an alpha particle
What is an alpha particle?
A particle with 2 protons and 2 neutrons, identical to a helium atom
What happens during alpha decay?
The original atom loses protons, meaning that when the alpha particle is ejected, two new atoms are formed as a result of this nuclear decay
How does beta decay occur?
When the nucleus ejects a beta particle
What is a beta particle?
It is identical to an electron, very small, light and negatively charged
What happens during beta decay?
A neutron is converted to a proton in the nucleus. This means the number of protons (and the atomic number) increases by 1.
What does Gamma decay involve?
Existing particles rearranging into new positions
When Gamma decay happens what is released?
Gamma radiation ( extremely powerful and can cause significant harm to living things)
What is the nucleus called after decaying?
A daughter nucleus
What is the speed of an Alpha particle?
10% speed of light
What is the speed of a Beta particle?
90% speed of light
What is the speed of Gamma rays?
Speed of light
What sort of particle is an alpha particle?
Helium nucleus
What sort of particle is a Beta particle?
Electron
What sort of particle are Gamma rays?
None (very high energy radiation)
What is the charge of an alpha particle?
+2
What is the charge of a Beta particle
-1
What is the charge of Gamma rays?
0
What can an alpha particle be stopped by?
A layer of dead skin or paper
What can a beta particle be stopped by?
1mm sheet of aluminum
What can Gamma rays be stopped by?
A thick slab(many cm thick) of concrete or lead
Why can alpha radiation be blocked quite easily?
Because the particles are large and slow
Can alpha radiation be deadly if breathed in?
Yes
What can Beta particles cause?
Radiation burns
What is Gamma radiation a form of?
Electromagnetic radiation
What can Gamma radiation cause?
Causes cells to mutate, damaging cells and can cause cancer
Why do some elements on the periodic table have their mass number in brackets?
It is the mass of the longest-lived isotope. This tells us that the atoms of these elements are unstable, likely because of their huge nucleus.
Who first coined the word ‘radioactivity’?
Marie Curie
Who discovered two types of radiation - that of alpha and beta decay?
Ernest Rutherford
What does radiology involve?
The use of high-energy radiation directed at cancer cells to kill them
What does nuclear imaging involve?
The patient is injected with radioisotopes, which are distributed around the body and emit small amounts of gamma radiation which are detected to show the organ structure of the body
