237563
Description
Flashcards by dominique22, updated more than 1 year ago
|
Created by dominique22
over 10 years ago
|
|
| Question | Answer |
| What's in the nucleus of an atom? | Neutrons and Protons |
| What is orbiting around the outside? | Electrons |
| Who can up with the 'Plum Pudding' model? In what year? | J.J. Thomson; 1897 |
| What did Ernest Rutherford do? What did it consist of? | He came up with the 'Gold Foil Experiment.' They took the radioactive substance, Radium, and shot positively charged particles at a thin piece of gold foil. They placed photo film around the outside to mark any particles it hit. |
| What happened during Rutherford's experiment? | -Most of the particles hit point A and went straight through the film. -Some slightly changed directions and hit places like point B. -Others bounced right back and hit point C. |
| What later on happened to Thomson's model? | It didn't fit Rutherford's observations. It wasn't detailed enough. |
| What is the mass number? | The total number of protons and neutrons |
| What is the atomic number? | The number of protons |
| What are isotopes? | They are different forms of the same element b/c they have different masses because the nuclei are different. BUT they have SAME properties and chemical reactions. |
| Give example of types of isotopes. | Hydrogen-1, Hydrogen-2 (deuterium), Hydrogen-3 (tritium) Uranium-234, Uranium 235, Uranium-238 |
| Give example of types of isotopes. | Hydrogen-1, Hydrogen-2 (deuterium), Hydrogen-3 (tritium) Uranium-234, Uranium 235, Uranium-238 |
| Give some uses of Radioactive Isotopes. | -Cancer treatment, -leak detection, -medical tracers(iodine in to the thyroid), -monitors of metal thickness, -sterilization of medical equipment, -food irradiation |
| What is nuclear fission? | -when the nucleus become unstable and splits into 2 smaller particles of a smaller mass and gives out 2-3 new neutrons. |
| If the nucleus DOES capture a neutron, what may happen? | 1. Nuclear fission= two nuclei of the same mass 2. B-decay = formation of transuranic elements |
| What is the missing mass? | It is converted into ENERGY!!! The therory of relativity (E=Mc2) by Einstein. :) |
| Possibilities of CHAIN REACTIONS for neutron bombardment | a) Neutron is captured by the nucleus, and fission does not occur. ----> Beta decay b) Neutron misses the nucleus and escapes from the sample c) Neutron is captured by another Uranium aton and continues the fission reaction |
| Who was Henri Becquerel and what did he discover, and when? | A french scientist who discovered Uranium in 1896 |
| What did Marie Curie and her husband,Pierre, discover? | -ALL uranium ores are RADIOACTIVE!!! -2 new elements:RADIUM and POLONIUM |
| Who else was involved in this? | Ernest Rutherford |
| What was used in Rutherford's experiment? | He put radium in a hole in a lead block to form a beam of radiation. He used magnets to form a magnetic field. |
| What did he find? | The beams that bent had opposite charges (+ & -) and a part of beam didn't bend at all (gamma ray with no charge). Negative bent farther than positive = positive beam was lighter No bending= no charge |
| What are the 3 types of radiation? | |
| Is the alpha particle: positive or negative? | Positive |
| How far can a beta particle penetrate? What can stop it? | A few meters in the air; aluminum and wood |
| What speed do alpha particles move at? | 1/10 the speed of light |
| How far can an alpha particle penetrate? What can stop it? | A few cm in the air; a piece of paper |
| Are gamma ray's particles? T or F | False |
| What are they? | They are electromagnetic rays |
| Gamma rays move at the speed of light. T or F | True |
| What does meta stable mean? | When the nucleus is unstable and decays by X-rays only. |
| Alpha particles have Helium nuclei, what type of decay do they undergo? | |
| What can stop the penetration of gamma rays? | 2-3 cm of lead or concrete |
| Gamma rays can be FULLY ABSORBED. T or F | False!!! Lead or concrete will absorb most but it will never stop all rays. |
| What are the sizes of alpha & beta particles, and gamma rays? | Beta= 1/2000 Alpha= 4 Gamma= 0 |
| What is 'half-life?' | **the amount of time for a 1/2 of the atoms in a substance to decay** |
| What will the half-life for a given isotope be? | IT WILL ALWAYS BE THE SAME!!! |
| what is the half-life for radioactive isotopes? | ~the amount of time it takes for the radioactivity to fall to half of the original value~ |
| To show radioisotopes decay use a pictograph. True or False | False; Use a decay curve |
| What are the main parts of a thermal nuclear reactors? | the coolant the moderator the control rods the radiation shield the nuclear fuel |
| Name the typical substances that are used as moderators. | i.e. graphite, carbon dioxide, heavy water (contain deutrium), normal water |
| What is a control rod used for? | Control rods are used to control the nuclear fission reactions that go on in the reactors |
| What is the purpose of coolant? | To take the heat away from the fuel rods and maintain a constant temperature. |
| Some of the heat can be used as an exchange to spin the turbines for electricity. T or F | TRUE |
| What are the radioactive substances stored in? | Radiation shields that are made of thick concrete and steel structure. |
| Why are the 2 pieces of sub-critical Uranium-235 kept separate until activation? | Being separate DOES NOT support fission and gives it a smaller chance of a neutron to hit the nucleus and cause it to detonate. |
| The 2 sub-critical pieces of Uranium-235 are put together and become a... | Super-critical mass |
| Why are they brought together when it is time to detonate? | To form a super-critical mass, which will provide more a lot of neutrons to create a fission reaction |
| What is Nuclear Fusion? | The process of combining atoms by forcing them together |
| What is in a burning in stars and how much of it? | Hydrogen; 600 billion tons per sec |
| What are fusion reactions? | the mass difference between the starting and end products= energy |
| What is needed to overcome the repulsion and get a fusion of 2+ charged neutrons? | Very high temperatures |
| Where does this happen? | In a hydrogen bomb |
| What are the advantages of NUCLEAR FUSION?? | 1. they are not expensive, abundant, and safe 2. decaying products are NOT radioactive 3. produces more energy per amount of the original material > nuclear fission 4. no known substance can exist to sustain high temps. like this in an reactor to give out electric energy |
| How do you COMPLETELY stop a nuclear reactor for an emergency? | Put the control rods all the way down!! |
| What element is needed the most nuclear fission reactors? | Uranium-235 |
| What percentage of uranium does nuclear fission need to continue the reaction? | 2.3% |
| How much does naturally occurring Uranium consist of? | 0.7% |
| The pellets of enriched Uranium-235 are contained in rods of steel. T or F | FALSE!! They are contained in rod of aluminium. |
| How much have the Uranium-235 been enriched? | 90% |
| What are control rods made of? | Boron or Cadmium |
| Why do the reactors had radiation shields? | to protect the workers and nearby housing from being exposed to large amount of gamma rays given off by the reactors |
| 350 degrees Celsius is when water boils in an reactor. T or F | True!!!!!!! |
| What has to take place in thermal nuclear power stations in order to generate electricity? | boil water= steam to turn turbines |
Want to create your own Flashcards for free with GoConqr? Learn more.