Henri Becquerel found key imprint on photo, after uranium salt was left on top of the photo film
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Geiger counter
Electronic counter clicks each time radioactive material enters
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What are the types of radiation?
Alpha, Beta, Gamma
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Who discovered the types of radiation
Ruthford
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What else did Ruthford discover with Geiger
Ruthford discovered that the centre of all atoms was positively charged
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Why are substances radioactive?
Because the increasing size of the nucleus causes positive charges to repel more, creating an unstable nucleus. The instability lowers energy needed for particles to break apart the nucleus.
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Plum pudding model
A positive ball of charge with electrons
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Bohr
Introduced the theory of electrons orbiting the atom
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Radiation definition
The emission or transfer of radiant energy as particles, electromagnetic waves, sound etc.
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Radioactivity definition
The phenomenon of spontaneous emmition of radiation resulting from changes in the nuclei of atoms of the element
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State the relative masses of protons, neutrons and electons
Protons- 1, Neutrons-1, Electrons- 1/2000
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What is the atomic number
Number of protons
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What is mass number
Number of protons + neutrons
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Alpha emissions
-Made up of two protons and two neutrons. Atomic drops by 2, mass drops by 4
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Beta emissions
- Too many neutrons compared to protons. Atomic increases by 1, mass number stays the same because the neutrons will change into protons
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Gamma emissions
Its uncharged and has no mass so emissions don't change number of protons or neutrons
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Neutons emissions
Emitted rarely due to alpha particles colliding with unstable nucleus, making it more unstable. Passes through substances easier than alpha and beta because the emissions are uncharged
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How do objects become ionising
As radiation can knock out elections, they become charged and therefore ionising
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What is radioactive contamination
When radiation is transferred between materials when they come in contact
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Whats the most dangerous radiation for people
Alpha because it has the strongest ionising power
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What is nuclear fission?
When larger molecules split to form two smaller nuclei with the release of two or three fission neutrons and gamma radiation
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How does a nuclear reactor work
The water slows down fission by increasing the number of collisions (moderator). Chain reaction is kept under control by control rods which absorb surplus neutrons. Hot rods are cooled with water. Kinetic energy increases. Energy t
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Other cards in this set
Card 2
Front
Geiger counter
Back
Electronic counter clicks each time radioactive material enters
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