Atomic Structure Flashcards
atoms have the same number of what?
protons and electrons
before the discovery of the electron, what were atoms thought to be?
atoms were thought to small spheres that could not be divided
Give 2 fuel sources of fission.
Uranium and Plutonium
Give 2 reasons why radioactive iodine is ideal for diagonising blocked kidneys.
1) It decays quickly into a stable substance.
2) Its half life lasts long enough for the test.
Give 2 things nuclear radiation is used for.
exploration of the internal organs
control or destruction of unwanted tissue.
Give 3 differences of the plum pudding model and the nuclear model.
1) The nuclear model says that the atom is mostly empty space, whereas the plum pudding model says that the whole atom is positively charged with negatively charged electrons embedded in it.
2) The nuclear model shows that most of the mass of the mass is in the centre of the atom, whereas the plum pudding model says that the atom full and does not have a specific place with more mass.
3)The nuclear model shows that only the centre of the nucleus is positively charged, whereas the plum pudding model says that the whole atom is positive with negative electrons imbedded in it.
How did the gold foil experiment disprove the plum pudding model?
The alpha particles were deflected and even reflected by the the gold nuclei because the positively charged particles repelled each other. This disproved the plum pudding model by showing that most of the mass was in the centre of the atom and most of the atom was empty space, which means that the whole atom is not positively charged
How do we induce nuclear fission?
By providing more nuclei for the produced neutrons to be absorbed into.
How does nuclear fission generate electricity?
The energy released from fission heats up water into steam which travels and turns a turbine. When the turbine turns, the generator generates electricity.
In beta radiation, what is the source of the beta particle?
A neutron decaying into a proton and electron
Later experiments led to the idea that the ____ charge of any nucleus could be subdivided into a whole number of _____ particles, each particle having the same amount of ______ _____. The name _____ was given to these particles.
positive, smaller, positive charge, proton
Put all the types of radiation in order of most to least ionising.
Alpha, Beta, Gamma
What are 2 pros of nuclear energy?
Uranium or plutonium fuel is relatively cheap
Doesn’t produce greenhouse gases
What are 3 cons of nuclear energy?
Power plants are very expensive to build
Nuclear waste is expensive to get rid of
Risk of nuclear meltdown
what are ions?
atoms with a different number of protons and electrons
What are the 3 types of radioactive decay?
alpha, beta, gamma
What are the relative charges of the particles found within the atom?
proton: +1, neutron: 0, electron: -1
What are the relative masses of the particles found within the atom?
proton: 1, neutron: 1, electron: 0
what atomic model did the discovery of the electron lead to?
The plum pudding model.
what charge do atoms have?
neutral
What device is used to record radioactive decays?
Geiger - Muller tube and counter
What did James Chadwick prove?
The existence of the neutron in the nucleus.
What did James Chadwick prove?
The existence of the neutron in the nucleus.
what did Niels Bohr add to the nuclear model?
He proved that the electrons orbit the positively charged centre at specific distance which we now call shells.
What do the control rods do?
they absorb different amounts of neutrons to manage the rate of fission.
what does a moderator do?
It slows the neutron down to the speed it needs to be absorbed by the nucleus.
what does the plum pudding model suggest about the atom?
the atom is a ball of positive charge with negative electrons embedded in it.
what happened in the gold foil experiment?
Alpha particles were fired at a sheet of gold foil and a detector detected the radiation they emitted and showed whether they passed through the foil or deflected.
What happens in nuclear fusion?
2 light nuclei fuse together to create a larger nucleus. In this process energy is released.
What is a radioactive tracer?
It is a radioactive substance that leaves a trace as it moves through the body. It can be detected by a detector.
What is a side effect of radiotherapy?
Some healthy cells may also be damaged or killed
What is an advantage of nuclear fusion?
Does not produce nuclear waste
what is an isotope?
An atom of an element with a different number of neutrons.
What is background radiation?
the radiation always present in the environment.
what is count rate measured in?
Becquerels (Bq)
What is each type of radiation stopped by?
Aplha: paper, Beta: aluminium, Gamma: Thick concrete/lead
what is half life?
Half life is the average amount of time it takes for a specific amount of radioactive source to halve by decaying.
what is irradiation?
When an object is exposed to radiation
What is radioactive contamination?
the unwanted presence of materials containing radioactive atoms on the other materials.
What is the fusion reaction that happens in the sun?
Hydrogen nuclei fusing to become helium nuclei
What is the process of nuclear fission?
1) A neutron is absorbed by a large nucleus.
2) The nucleus splits into 2 smaller nuclei.
3) It releases energy and radiation as well as 2 or 3 neutrons.
what is the range of each type of radiation in air?
alpha: 2-5cm, beta: 30cm, gamma: infinite
what kind of particle is a beta particle?
high energy electron
what particles are the nucleus made up of?
Protons and Neutrons.
what type of particle is a gamma particle?
Electromagnetic wave photon
what type of particle is an alpha particle?
helium nucleus
What type of radiation is used in external radiotherapy?
Gamma
What type of radiation is used in internal radiotherapy?
Beta
what type of reaction is nuclear fission?
induced chain reaction.
What will happen to cells that receive a large dosage of radiation?
the cells will die
Where does nuclear fusion happen?
In the sun
where is most of the atom’s mass?
In the nucleus
Which 3 particles are found within the atom.
Proton, Neutron and Electron
which expirement led to the nuclear model replacing the plum pudding model?
the gold foil experiment by Ernest Rutherford.
Which three symptoms are common symptoms of radiation sickness?
vomiting, hair loss, tiredness
why can we not do nuclear fusion on earth right now?
It requires extremely high temperatures and pressures which we cannot create
Why do most radioactive tracers emit gamma radiation instead of alpha or beta?
Gamma radiation has a high penetrating power, so can reach outside the body. Alpha and Beta radiation are both too powerful inside the body and can damage the body.
Why does fusion release so much energy?
Some of the mass is converted into energy
