P7: Radioactivity Flashcards
(39 cards)
Who discovered radiation?
Henry Becquerel
What is nuclear radiation?
Nuclear radiation is the release (emission) of energy from the nucleus in the form of moving electromagnetic waves or as the movement of subatomic particles
What are the 3 different types of radiation?
- Alpha
- Beta
- Gamma
Why would a substance/element become radioactive?
A substance/element would become radioactive when it has too many neutrons or protons meaning it has an unstable nucleus, it therefore has to release energy (decay the nucleus) so the nucleus can become stable
What is the unit of radioactivity?
Becquerels (Bq)
What is background radiation?
Small doses of radioactive particles in the air that are produced naturally,
they not dangerous as they are in such small doses but can be picked up by a Geiger counter
What are 2 sources of background radiation in our everyday lives?
- A banana
- Background radiation in the air
What is a Geiger counter?
A device that clicks when it detects ionising radiation, it clicks more frequently when the amount of ionising radiation it is detecting is larger
What is the plumb pudding model?
A model of the atom created by Joseph John Thompson in which there is a ball of positively charged matter with electrons sitting inside it (scattered around)
What were the 3 main observations that Ernest Rutherford made from the Gold Foil Experiment?
Most of the atom is empty space - The large majority of the alpha particles past straight through the gold foil undeflected
There is a small dense area in the middle of the atom - Some of the alpha particles deflected back from the foil
The small dense area is positively charged - Some of the negatively charged alpha particles deflected at small angles away from the gold foil
Who carried out the gold foil experiment and what was it?
It was carried out by Ernest Rutherford and it included him shooting alpha particles at a thin sheet of gold foil
What is the atomic (mass) number of an element?
The amount of protons + neutrons
What is the proton number of an element?
The amount of protons
What is a radioisotope?
An isotope that is radioactive (e.g carbon 14)
What is an isotope?
An atom with a different number of neutrons to it’s usual element
How many protons and neutrons does an alpha particle consist of and what is it?
It consist of 2 protons and 2 neutrons and it is a fast moving helium atom
What happens to an atom when it undergoes alpha decay?
It loses 2 protons and 2 neutrons
What is alpha radiation?
Alpha radiation is the nucleus of a helium atom travelling at extremely high speeds
What does a beta particle consist of and what is it?
A beta particle consists of one electron and it is a fast moving electron
What happens to an atom when it undergoes beta decay?
One of the atoms neutrons is converted into a proton and an electron, but the atom also loses one electron
therefore the mass number stays the same but the atomic number increases by 1
What happens to an atom when it undergoes gamma decay?
The atomic structure of the atom does not change at all
True or False: The decay of an unstable nuclei happens randomly
True - It is impossible to predict when a nuclei will decay as each nuclei has the same chance of decaying at all times
What are the symbols of alpha, beta and gamma radiation?
Alpha - a
Beta - B
Gamma - Y
Order the 3 types of radiation (alpha, beta and gamma) from longest range in air to shortest range in air?
1) Gamma - Unlimited
2) Beta - 1 meter
3) Alpha - 5 centimetres
