P7 - Radioactivity Flashcards
What is the nucleon number?
Number of protons plus neutrons
What is the relative masses of a proton, neutron and electron?
Electron - 0.0005
Proton - 1
Neutron - 1
Is the proton number on the bottom or top on the periodic table symbol?
It is on the bottom and is always the smaller number
What is ionising radiation?
The radiation emitted from unstable nuclei, that when in contact with a neutral atom can dislodge an electron and make it an ion. Made up of alpha, beta and gamma radiation.
Describe dalton’s model of the atom.
-All matter is made up of small, indivisible spheres.
-atoms of the same element are the same size and weight.
-During chemical reactions atoms rearrange to form different substances.
Describe the plum pudding model.
Atoms are positively charged spheres, with negatively charged electrons embedded within, like plums in a pie.
Describe the gold foil experiment?
It involved bombarding a thin sheet of gold foil with alpha particles, surrounded by a material that flashed when in contact with the alpha material.
Who created the gold foil experiment?
Ernest Rutherford
What were the takeaways from the gold foil experiment?
-showed nucleus was very, very small
-showed atom was mostly empty space
-most of atoms mass in nucleus
-nucleus was positively charged
What does ionising mean?
How well it rips off electrons .
What is the unit for radioactivity?
Becquerells (Bq)
What is an alpha particle?
A helium nucleus
What is a beta particle?
A fast moving electron
What is a gamma particle?
A wave
What stops the different radioactive particles?
Alpha - skin/paper
Beta - thin aluminium
Gamma - thick lead