12. P7 Radioactivity Flashcards
Name the three types of radiation given out by unstable isotopes?
Alpha Beta Gamma
What will stop alpha radiation?
Sheet of paper
What beta radiation can be stopped using?
3-5mm of Aluminium
What gamma radiation can be stopped using?
5-10 cm of lead
What is alpha radiations range in air?
up to 5cm in air
What is beta radiations range in air?
up to 1m in air
What is gamma radiations range in air?
over 1km in air
What is alpha radiation made up of?
2 protons and 2 neutrons
What is beta radiation made up of?
fast moving electron
What is gamma radiation made up of?
Energy (electromagnetic wave)
Which type of radiation is the most highly ionising?
Alpha
Which type of radiation travels at the speed of light?
Gamma
Which type of radiation is not affected by a magnetic or electric field and why?
Gamma as it does not have charge
The charge of an alpha particle?
Positive
The charge of a beta particle?
Negative
Name of scientist who discovered the electron and put forward the plum pudding model fo the atom?
JJ Thompson
What equipment did Rutherfords assistants use in order to test the plum-pudding model?
Thin gold foil, microscope with zinc sulphide screen, alpha source in lead shield with narrow opening, all within a vaccuum.
What observations were made from Rutherford’s experiment?
1) Most of the alpha particles passed straight through, 2) Few were deflected at small angles, 3) Very few were repelled at large angles(>90degrees) back in the direction of the source
What were Rutherford’s conclusion from the Alpha-scattering experiment?
1) Most of the atom is empty space, 2) Contains a small positively charged point which contains most fo the mass.
Where is all radiation emitted from
Nucleus of unstable isotope
Why did Rutherford carry out the alpha scattering experiment all within a vacuum?
So the air would not affect the path of the alpha particles. Alpha particles are easily absorbed by air and only have a range of upto 5cm.
Name given to the model of the atom which displaced Thompson’s Plum-pudding model after Rutherfords results?
Nuclear Model
Name of the scientist who adapted Rutherfords model to include the electrons orbiting around the nucleus and existing in “shells”?
Neils Bohr
Name of scientist who found direct experimental evidence for the existence of the Neutron which was found alongside protons in the nucleus?
James Chadwick
What does the atomic number of an element tell us?
The number of protons in the nucleus
What does the mass number of an element tell us?
The number of protons and neutrons in the nucleus.
What is meant by an isotope?
An element with the same number of protons but different number of neutrons.
What happens to the proton number when an unstable isotope emits an alpha particle?
Goes down by 2