atoms and isotopes (topic 4) Flashcards
(6)
structure:
- alpha particle consists of a helium nucleus
- alpha particle consists of 2 protons and 2 neutrons
- a beta particle is an electron
- a beta particle comes from the nucleus
penetration:
- alpha particles are very poorly penetrating
- alpha particles can penetrate a few cm in air
- alpha particles are absorbed by skin
- alpha particles are absorbed by thin paper
- beta particles can penetrate several metres of air
- beta particles can pass through thin metal plate / foil
- beta particles can travel further than alpha particles in air
- beta particles can travel further than alpha particles in materials like metals
deflection:
- alpha particles and beta particles are deflected in opposite directions in
an electric field
- beta particles are deflected more than alpha particles
- alpha particles have a greater charge than beta particles but beta particles have much less mass or beta particles have a greater specific charge than alpha particles
- smaller than
- radon loses an alpha particle
what is the mass number the same as
number of protons and neutrons
what is the atomic number
number of protons
in an atom what two things are the same number
electrons and protons
what type of radiation does a smoke detector emit
alpha
electrons
an alpha particle does not have any
electrons
are highly ionising
(1)
neutron discovered
1 and 0
very small and -1
(3)
- has a nucleus which is positive charge
- negative charged electrons
- orbit nucleus
90
100
157
y and z
same number of protons
what part of an atom determines its element
proton
(3)
- A: alpha particle passes straight through the empty space of the atom
- B: alpha particle deflected by the positive nucleus
- C: alpha particle heading straight for the nucleus is deflected backwards
(6)
- alpha particle scattering experiment
- alpha particles directed at gold foil
- most alpha particles pass straight through
- (so) most of atom is empty space
- a few alpha particles deflected through large angles
- (so) mass is concentrated at centre of atom
- (and) nucleus is (positively) charged
- plum pudding model has mass spread throughout atom
- plum pudding model has charge spread throughout atom
- alpha radiation is P because alpha particles are positively charged
- gamma radiation is Q because gamma rays are neutral
- (so beta particles are negatively charged)
to inject… tracer
or (a neutral atom has no overall charge, explain this in terms of its particles) (2)
- equal numbers of protons and electrons
- protons and electrons have equal but opposite charge
3 fewer neutrons
neutron
nuclear fission
90
140
(3)
- alpha (particle)
- mass number goes down by 4
- number of protons and neutrons goes down by 4
- or number of neutrons goes down by 2
unstable isotopes are unstable because their ratio of neutrons to protons causes an imbalance in the energies working to hold the nucleus together or push the nucleus apart)
L
J
K
cosmic rays from space
- nuclear power
- nuclear accidents
- different number of / fewer protons
- or different atomic number
which is the atomic/proton number
top number
which is the atomic mass number
bottom number
168
how many people in each group developed cancer
describe the structure of the atom in the plum pudding model (2)
- sphere of positive charge
- negative charges dotted throughout the atom
draw an isotope of the nucleus of lithium
- number of protons = 3
- different number of neutrons
- expect to see 2,3,5, or 6 neutrons
