Atoms and Radiation Flashcards
What is a Geiger Muller Tube used for?
To detect radiation
What is the Ionising power of:
Alpha, Beta and Gamma particles?
Alpha - Very strong
Beta - Medium
Gamma - Weak
What is emitted from an Alpha particle nucleus?
Helium nuclei
Atomic Number - 2
Atomic Mass - 4
What is emitted from an Beta particle nucleus?
Electron
Atomic Number - 0
Atomic Mass - -1
What is emitted from a Gamma particle nucleus?
Electromagnetic wave
Why are atoms neutral?
Because the number of positive protons is equal to the the number of negative electrons the atom has.
Compare the ‘Plum Pudding’ Model and the ‘Nuclear’ Model:
- Plum pudding - a sphere of positive charge with electrons embedded within.
- Nuclear model - negative electrons orbit positive nucleus
Explain Rutherford’s scattering experiment the conclusion.
Alpha particles were fired at a thin sheet of gold.
Most alpha particles passed through.
Conclusion: Most of the atom was empty space and the mass was concentrated at the centre.
Some positive alpha particles were deflected so the nucleus must be positive.
What stops an Alpha, Beta and Gamma particle?
Alpha - Skin or a sheet of paper
Beta - Thin sheet of aluminium
Gamma - Thick lead or concrete
What is activity?
The rate at which a source of unstable nuclei decays.
What causes an atom to be unstable?
The atom doesn’t have enough binding energy to hold the nucleus together due to an excess of either protons or neutrons.
What is a Count rate?
The number of decays recorded each second by a detector.
What is Half Life?
The time it takes for the number of nuclei in an unstable atom to halve.
What is an Isotope?
The same element with the same number of protons but different amount of neutrons.
Give one use of An Alpha, Beta and Gamma particle:
Alpha - Smoke Detector
Beta - Thickness Gauge
Gamma - Radiotherapy
What is contamination?
An object taking in radiation as a source.
What is irradiation?
An object is exposed to radiation from an radioactive substance.
