P7-Radioactivity Flashcards
A radioactive substance contains an…
Unstable nuclei that becomes stable
How does an unstable nuclei become stable?
By emitting radiation
3 main types of radiation form radioactive substances
Alpha
Beta
Gamma
Rutherford used _ particles to probe inside _. He found that some of the _ particles were _ through large angles
Alpha
Atoms
Alpha
Scattered
Isotopes of an element are
Atoms with the same number of protons but different number of neutrons
They have the same atomic number but different mass numbers
What are alpha particles composed of?
Two protons and two neutrons
Which radiation type has the greatest ionising power?
Alpha
Beta radiation consists of
Fast moving electrons emitted from the nucleus
Gamma radiation consists of
Electromagnetic radiation
Alpha, beta and gamma radiation…
Ionise substances they pass through
Ionising in a living cell can damage or kill the cell
The half-life of a radioactive isotope is
The average time it takes for the number of nuclei of the isotope in a sample to have
The count rate of a Geiger counter caused by a radioactive source…
Decreases as the activity of the source decreases
How useful a radioactive isotope is depends on…
Its half life
The type of radiation it gives out
Nuclear fission is the…
Splitting of an atom’s nucleus into two smaller nuclei and the release of 2 or 3 neutrons and energy
Induced fission occurs when…
A neutron is absorbed by a uranium-235 nucleus or a plutonium-239 nucleus and the nucleus splits
