Karteikarten
Physics - P4 - Atomic Structure
Karten in diesem Stapel (55)
- 1Describe the Greek model of the atom in eight words.Tiny spheres called atoms which were indivisible.
- 2Democritus originally came up with which model of the atom?The Greek model
- 3John Dalton agreed with the Greek model but theorised that each element had: (the same/a different) atom.A different atom.
- 4Who was credited with discovering electrons?J J Thompson
- 5What model of the atom did J J Thompson theorise?Plum pudding model.
- 6Who came up with the first nuclear model?Ernst Rutherford
- 7What experiment did Rutherford use to discover the first nuclear model?Alpha scattering experiment.
- 8What results were expected from the alpha scattering experiment and why were they expected?The expected results were that particles would pass through or for a select few be deflected because of the plum pudding model.
- 9How does the prediction of the alpha scattering experiment compare to the results?They expected particles to pass through or be deflected and they passed through but some deflected more than expected.
- 10What did the results of the alpha scattering experiment prove?1) Mass was concentrated in the centre.
2) The nucleus had a + charge.
3) Most of the atom was empty space. - 11Niels Bohr suggested that orbiting electrons do so at different distances called what?Energy levels.
- 12James Chadwick proved the existence of which sub atomic particle and what did it help to explain?Proved existence of neutron to explain the imbalance between the atomic and mass numbers.
- 13The nucleus contains which two sub atomic particles?Protons and neutrons.
- 14What charges does each sub atomic particle in a nucleus have and what is the overall charge of a nucleus?Proton: +1
Neutron: 0
Nucleus: + - 15The radius of the nucleus is about (100/1,000/10,000) times smaller than the radius of the whole atom.10,000
- 16Most of an atom is comprised of mostly what?Empty space.
- 17What sub atomic particles orbit the nucleus and what charge do they have?Electrons with -1 charge.
- 18The number of protons is equal to the number of what? Why is this?Electrons
This is because the charges then even out. + and - charges cancel out. - 19What are isotopes?Isotopes are different forms of the same element.
- 20All isotopes have the same number of which sub atomic particle?Protons
- 21The number of protons defines the atomic _____ of an element.Number
- 22The mass number of an atom is the sum of the total of which sub atomic particles?Protons and neutrons.
- 23Isotopes have differing numbers of which sub atomic particle?Neutrons.
- 24How many elements have isotopes?All of them!
hOW maNy Of thOsE aRe sTable?
It's a code. Figure it out! - 25What happens to the unstable isotopes and why do they do this?They decay into other elements and emit radiation as they try to become more stable
- 26What is radioactive decay and why does it happen?Radioactive decay is when isotopes emit radiation while balancing the sub atomic particles to become more stable.
- 27What are the three main types of radiation?Alpha
Beta
Gamma - 28Alpha particles are what type of nuclei and why is this?They are helium nuclei as the alpha particles have two protons and two neutrons.
- 29How penetrating is alpha radiation?Low
- 30How far does alpha radiation travel?Around 3-5 cm. Basically just a few cm.
- 31What is alpha radiation stopped by?A sheet of paper.
- 32How ionising are they?Very ionising.
- 33Put the types of radiation in terms of ionisation. Starting with the highest.Alpha
Beta
Gamma - 34Put the types of radiation in order of distance travelled. Starting with the highest.Gamma
Beta
Alpha - 35What is beta radiation?A fast moving electron.
- 36What is gamma radiation?An electromagnetic wave.
- 37Nuclear equations show radioactive _____ by using element symbols.Decay
- 38How are nuclear equations written?atom before decay ---> atom after decay + radiation emitted.
- 39What is the golden rule when writing nuclear equations?The total mass and atomic numbers must BE THE SAME!
- 40Alpha decay __________ the charge and mass of the nucleus.Decreases.
- 41Why does the mass and charge decrease when alpha decay occurs?Because a helium nuclei is released during alpha decay.
- 42When alpha decay occurs, how much is the atomic number and mass number reduced by?Atomic: 2
Mass: 4
Why do you think this is? - 43Why is the charge reduced during alpha decay?Because protons are being removed from the isotope. Protons are + charged therefore you are left with a negative charge.
- 44Uranium 238 becomes Thorium 234 during alpha decay. Write a nuclear equation to show this.238 ---> 234 + 4
92 ---> 90 + 4
U ---> Th + He - 45Beta decay increases the _____ of the nucleus.Charge
- 46Why does beta decay increase the charge of a nucleus?Because the process involves losing an electron so as a result the charge increases as electrons have a negative charge.
- 47Does the mass or charge change during gamma decay? Why or why not?No because there is no change to atomic mass or number because gamma decay just removes excess energy.
- 48Radioactivity is a (controlled/random) process.Random
- 49What is half life?Half life is the amount of time needed for the radiation emitted to half. (Also called the amount of activity)
- 50What is half life measured in?Becquerels
Bq - 51The radioactivity of a source _________ over time.Decreases
- 52When does the activity of a radioactive source reach zero?It never does.
- 53The initial activity of a sample is 640Bq. Calculate the final activity as a percentage of the initial activity after 2 half lives.25%
- 54How can you measure the half life using a graph?Find the time interval corresponding to the activity twice and then find the difference of the time intervals.
- 55—
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- Der Nutzer hat seine Fachbereichs-Information gelöscht. Karteikarten am Physics - P4 - Atomic Structure, erstellt von Gelöschter Nutzer am 18/06/2018.
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- Erstellt von Ein gelöschter Nutzer · 30 Okt 2016
- Kopiert von Robin Skailes · 18 Jun 2018
- Kopiert von Robin Skailes · 18 Jun 2018
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