Atomic structure Flashcards
What are isotopes
Atoms of an element that have a different number of electrons to usual
What do radioactive substances give out when they decay
Alpha, beta or gamma radiation and can give off neutrons too
What are alpha particles
Helium nuclei
What is alpha radiation used in
Smoke detectors
Ionises air particles which causes a current to flow. If there is smoke in the air it binds to the ions - meaning that the current stops and the alarm sounds
What is a beta particle
An electron
What are beta particles used for
Test the thickness of sheet of metal as the thickness affects the amount of radiation passing through the sheet
What are gamma rays
Waves of electromagnetic radiation (0.0)
What are gamma rays used for
To sterilise medical equipment
What is radioactivity as a process
Completely random
What can radiation be measured with
Geiger-Muller tube and counter
What is activity measured in
Becquerels
What is the half-time
The time taken for the number of radioactive nuclei in an isotope to halve
OR
The time taken for the count-rate to half
What is background radiation
The low-level radiation that is around us all of the time
Where does background radiation come from
Naturally occurring unstable isotopes which are all around us (eg rocks and food)
Space - cosmic rays which come mainly from the sun
Human activity (eg fallout from nuclear explosions)
What is exposure to radiation called
Irradiation
What is contamination
When radioactive atoms get into/onto an object
Which types of radiation are most dangerous outside the body
Beta and gamma
Which types are most dangerous inside the body
Alpha as they are the most ionising
What is radiotherapy
Gamma rays are directed at the right dosage to kill the cancer cells without damaging too many normal cells
Risks to using radiation
Can damage cells by either killing or causing them to mutate
What is nuclear fission
Splitting of a large unstable nucleus
Forms 2 lighter elements
Releases neutrons
Can start a chain reaction
What can the energy released by nuclear fission be used for
Heat water or turn turbines or generators
How is the amount of energy produced in fission by a nuclear reactor controlled
Using control rods which absorb neutrons
What happens during nuclear fusion
2 light nuclei collide at high speed and fuse to create a lighter heavier nucleus
The heavier nucleus doesn’t have as much mass as the 2 separate light nuclei as some of the mass is converted into energy
