Radiactive Decay Flashcards
State the four types of nuclear radiation
Alpha radiation
Beta radiation
Gamma radiation
Neutron Radiation
What is meant by background radiation?
radiation all around us that is always present
Give the sources of background radiation
Food Nuclear Power Cosmic Rays Medical Radon Gas Ground/Buildings
How do you measure and detect background radiation?
Photographic film
Geiger Müller Counter
How is photographic film used to measure radiation?
A photographic film turns dark when it absorbs radiation. Helpful for those who work on radiation as the darker the film, the more radiation they know they have been exposed to.
How are Geiger-Muller tubes used to measure radiation?
When the Geiger-Muller tube absorbs radiation it produces a pulse, which a machine uses to count the amount of radiation. The frequency of the
pulse depends on how much radiation is present. A high frequency would mean the tube is absorbing a large amount of radiation.
What is an alpha particle
particle made of 2 neutrons, 2 protons
also known as a helium nucleus
What is an alpha particles stopping power
can travel a few cm in air, stopped by paper/skin
what is a beta particles stopping power
can travel a few m in air, stopped by aluminium foil
what is the stopping power for gamma particles
can travel many kms in air, stopped by thick concrete or led
label the types of radiation staring from the most to least ionising
most-alpha
middle-beta
least-gamma
How does gamma emission affect the mass/charge of an atom?
Both mass and charge remain unchanged.
Describe the plum-pudding model of the atom
A sphere of positive charge, with the negatively charged electrons distributed evenly throughout it
Which experiment led to the plum-pudding model being discarded?
Rutherford’s gold foil/ alpha scattering experiment
What is the name given to the model of the atom before Rutherford’s experiment ?
The Bohr
Describe Rutherford’s experiment
Alpha particles (charge +2) were fired at a thin sheet of gold foil:
Most particles went straight through
Some particles were deflected by small angles
A few particles were deflected by large angles
What are the conclusions of Rutherford’s experiment?
Most of an atom is empty space
The nucleus has a positive charge
Most of the mass is concentrated in the nucleus
What happens in the process of beta plus decay?
A proton turns into a neutron and a positron
What happens during Beta Minus Decay
a neutron turns into a proton and electron
When alpha decay occurs, what happens to the atomic number and the mass number of the atom?
The atomic number decreases by 2
The mass number decreases by 4
A new element is made since the atomic number has changed
What effect does beta minus decay have on the mass number and atomic number of an atom?
The mass number stays the same as the total number of neutrons and protons hasn’t changed (one has just turned in the other).
The atomic number increases since there is one more proton
