Atoms And Radiation Flashcards
Radioactive decay
- spontaneous and random
- can’t predict when or if a particle decays
Half life
Time taken for half of the nuclei to decay
Long half life
Less radiation for a very long time
Less dangerous immediately
Radiation is spread out
Stays dangerous for long
Short half life
Lots of radiation quickly
Immediately dangerous
Becomes safe after a short period of time
All of it comes out in a short period of time
Bq
Unit of activity
Becquerels
Proton
A positive particle in the nucleus
One of two nucleons
Neutron
A neutral particle in the nucleus
One of two nucleons
Nucleon
Total number of protons and neutrons in the nucleus of an atom
They’re both roughly the same size and account for most of the mass of the atom
Nucleus
The centre of the atom
You
Made up of positive protons and neutral neutrons
Nearly all of the mass of the atom is in the nucleus
Nuclide
A specific arrangement of protons and neutrons in a nucleus
Isotope
Two versions of an atom with the same number of protons and different number of neutrons
Random
Can’t be predicted
Spontaneous
Not caused by anything
Decay
When an unstable nucleus turns into a more stable nucleus (emits radiation)
Activity
Number of decay in a second
How do electrons absorb and emit radiation?
Based on the energy levels they move between
Different energy =
Different wavelengths
Ionisation
If electrons in an atom absorb nuclear radiation (alpha, beta or gamma) an electron can be completely removed
Removing an electron from an atom to create an ion
What can cause mutation?
If atoms inside a living cell’s DNA become ionised
Can lead to death, birth defects or cancer
Energy level
‘Shells’ inside an atom
Frequency
Number of complete waves every second
Mutation
Changing the DNA of a cell
Contamination
Radioactive mason or in something, which makes it radioactive
Irradiation
Putting radiation on something
Radioactive tracer
A radioactive isotope that you inject or feed into a living person to see where a person is
Why do nuclear weapons: power need nuclear fission?
So they can work
- this is triggered by a neutron
- this only works when a slow neutron hits the nucleus
Control rod
Control the reaction by absorbing neutrons
- if a reaction is going too fast, they’re lowered so the reaction slows down
- if it’s going too slowly they’re raised so the reaction gets faster
Nuclear fission
When a large unstable nucleus splits into two smaller nuclei releasing energy
- a big nucleus can undergo fission because all the protons repel each other
- it needs to absorb a slow neutron to undergo fission
