The Nucleus Flashcards
gold foil experiment
where is the source of α-particles contained
an evacuated chamber
gold foil experiment
where are the α-particles incident on
the gold foil; plane in perpindicular to direction of motion
gold foil experiment
how do you know there a α-particles
flashes of light are produced when they hit glas screen coated in zinc sulphide
gold foil experiment
why is the experiment carried out in a vacuum
to prevent α-particlees being deflected by collisions with gas atoms
gold foil experiment
what did the majority of α-particles do
pass straight through the metal foil; did not come close to repulsive +ve charge
shows atoms are mainky empty space
gold foil experiment
what happened when α-particles came sufficiently close to the nucleus
due to the +ve charge of α-particles and nucleus, they were ‘back-scattered’ at a large angle
what does the small size of the nucleus show
it is extremely dense
size of nucleus
sphere of radius ≈ x10-15
(Fm, femtometres)
what is the volume of a nucleus directly proportional to
mass number (total no. of nucleons in a nucleus)
what is the radius of a nuclues proportional to
mass number to the power of a third
constant of proportionality equation and number
r = r₀A¹⁻³
r₀ = 1.2x10⁻¹⁵ (constant for nucleus not atom)
r ∝ A¹⁻³
mass of nucleus equatiom
M = Am
m = mass of nucleon
density of nuclear matter (constant) equation
when r₀ is constant
ρ = Am / v
ρ = 3m / 4πr₀³
constant if r₀ constant = 2.3x10¹⁷
what does the huge density of the nucleus number show
that there is no empty space between particles in nucleus
