P4 atomic structure Flashcards
what is the radius of an atom
1 * 10^-10
what is an isotope
atom with different number of neutrons
what is EM radiation
when electrons change orbit (closer or further away)
-closer to nucleus emits more radiation
-further absorbs radiation
what did Dalton think about the atom
everything was made of tiny spheres that could not be divided
what did J.J Thomson think about the atom
plum pudding model was found which said the overall charge of an atom is neutral and the negative electrons were scattered on the positive body
what did Rutherford think of the atom
positive nucleus in the centre and negative electrons in a cloud around it
what is the gold foil experiment
alpha particles shot through
-most went straight through
-some slightly deflected
-few were deflected by more than 90 degrees
who perfected the final model of the atom
Bohr
what is radioactive decay
the act of atoms nuclei becoming unstable
what is activity
the rate at which a nuclei decays
what is count rate
number of decays recorded by a counter per second
what are some features of alpha radiation
-helium nucleus
-highly ionising
-weakly penetrating
-causes mass and charge of the nucleus to decay
what are some features of beta radiation
-medium ionising
-electrons
-medium penetration
-causes charge of nucleus to change
what are some features of gamma radiation
-low ionising
-highly penetration
what is half life
time taken for half the nuclei in an atom to decay
