Slides in this set
Discovery of the nucleus
· Rutherford carried out experiments to see what
happened when alpha particles (2 neutrons and 2
protons) were fired at metal foil.
· His Discoveries:
· Most alpha particles passed straight through the foil
· A few were deflected through a small angle
· About 1 in 1000 were deflected straight back
through 180 degrees.…read more
What this told us about the nucleus
· The inside of atoms must contain small
positively charged nuclei as a few of the alpha
particles were repelled and deflected.
· The nucleus is very small as only a few alpha
particles were deflected.
· The nucleus is concentrated in a tiny volume
as only a tiny percentage are deflected back
toward the observer.…read more
· Isotopes of a certain element have different
numbers of neutrons in their nucleus, but the
same number of protons.
· The mass number (A) will be different but the
atomic/proton number (Z) will be the same.…read more
Beyond fundamental particles
· There are two distinct groups of particles.
· HADRONS/BARYONS: Particles affected by the
strong nuclear force (protons/neutrons)
· LEPTONS: Particles unaffected by the strong
nuclear force (electrons)…read more
· Inside hadrons are quarks each hadron is made up
of three quarks.
· There are six `flavours' of quarks up, down,
strange, top, bottom, charm.
· Each quark has its opposite antiquark.
· The properties of hadrons are the sum of the
properties of its constituent quarks.…read more