Term
| Known Observations before Dalton |
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Definition
1. most natural materials were mixtures of pure substances
2. pure substances are elements or compounds
3. a given compound always contains the same relative mass of the elements |
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Term
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Definition
1. elements are made up of small particles called atoms
2. all atoms of a given element are identical
3. the atoms of one element are different than atoms of another element
4. atoms of one element can combine with atoms of another element to form compounds
5. atoms are indivisible in chemical processes (chemical reactions invovle exchanging atoms between compounds) |
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Term
| JJ Thomson's 3 Experiments |
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Definition
1. use magnets to bend/move ray through little hole in cathode ray tube so he can count the charge (**shows that ray and charge are the same thing)
2. use cathode ray tube with battery to determine if charge was + or - (**confirms charge is -)
3. Try to figure out how heavy the charges are by using magnets of varying strength (**weak magnets move the beam, therefore what is in the beam is very, very light OR heavily charged --> weakness of 3rd experiment)
DISPROVE DALTON'S THEORY |
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Term
| Thomson's Model of the Atom |
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Definition
"Plum Pudding Model"
+ and - charges mixed together in a ball |
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Term
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Definition
-oil drop experiment
-succeeded in measuring charge of electron! by measuring charge on outside of oil drops
-e=1.6 x 10^-19 coulombs |
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Term
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Definition
-alpha particles with gold foil experiment
-only some go through, others deflect
-concludes that there are 2 areas of an atom --> must have big empty space and there must be somewhere that is very dense with + charge |
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Term
| Rutherford's model of the atom |
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Definition
-like normal model today
-except electrons aren't orbiting, just hanging out
-dense core with protons |
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Term
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Definition
-discovered isotopes
-said there were elements that were already known that had different radioactive properties yet identical chemical properties --> how it reacted with other elements |
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Term
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Definition
-discovered neutrons
-magnet/charge had no effect on particle that came out of Beryllium foil |
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Term
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Definition
-discovered neutrons
-magnet/charge had no effect on particle that came out of Beryllium foil |
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Term
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Definition
-levels in concentric circles outside of nucleus
-"quantized"--> when electron moves from one orbital to another
-correct -> electrons at different distances/levels of energy
-wrong -> too 2 dimensional |
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Term
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Definition
-different electron orbitals
-s, p, d
-spherical, dumbbells, clover, dumbbells with belt |
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Term
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Definition
-discovered shape of electron
-used needle with current |
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Term
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Definition
-n
-what shell e- is in --> how close/far from nucleus
-must always be + integer, 1, 2, 3, 4... |
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Term
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Definition
-L
-values of 0, 1, 2, 3, ... (n-1)
-L values tell you the shape of the orbital |
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Term
| Third/Magnetic Quantum Number |
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Definition
-Me
-can have following values, -L, -L+1, -L+2, ... -1, 0, 1, ... L-2, L-1, L
-tells you how many identical orbitals in shell |
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Term
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Definition
-Ms
-Uhlenbeck and Goudsmit
-electrons have "spin" |
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Term
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Definition
| orbitals tend to be more stable when either half filled or fully filled |
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Term
| Johann Wolfgange Doebereiner |
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Definition
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Term
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Definition
-Telluric Helix (1st periodic table)
-organized by mass and chemical reactivity
-"The properties of the elements are the properties of the numbers" |
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Term
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Definition
-first one to hit on periodicity
-volume vs. mass "Periodic Table" |
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Term
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Definition
-open spaces in periodic table --> SHOULD be an element (predicting periodicity)
-Errors/Shortcomings
1. offset transition metals because he didn't know where to put them
2. missed a whole group --> Noble Gases because none are known and doesn't predict they will be found
3. people interpreted that there were elements missing between H and Li (too MANY) |
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Term
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Definition
-discovered Noble Gases
-heats minerals to find them |
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Term
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Definition
-discovered x-rays
-metal at end of tube -> never would have discovered x-rays if there was no metal |
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Term
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Definition
-rock experiment --> rock emits energy! (U)
-discovers "radioactive decay" |
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Term
| Alpha Particles/Alpha Decay |
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Definition
-helium nucleus without e- --> +charged
-relatively massive
-won't penetrate sheet of paper
-could be emitted with other things, like gamma rays |
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Term
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Definition
- "-" charge
-relatively "massless"
-"electron"--> not normal electron because the origin is the NUCLEUS
-1/2 cm lead will protect you |
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Term
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Definition
-NOT a particle
-can accompany alpha and beta decay
-pure energey
-10 cm lead for protection |
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Term
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Definition
-VERY rare and dangerous
-largely produced by carbon-11, potassium-40, nitrogen-13, oxygen-15, chlorine-18, iodine-121 |
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Term
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Definition
-nucleus sucks in electron
-proton + electron = neutron
-x-rays |
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Term
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Definition
Sources:
1. electron capture
2. e- shot at a larger nucleus (metal) --> Roentgen |
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Term
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Definition
-will break apart in presence of neutrons
-decays/unstable |
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Term
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Definition
| can be prompted to decay under right circumstances |
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Term
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Definition
-accomplished NUCLEAR FISSION (first to do so)
-creates first self-sustaining nuclear reaction --> gets product neutrons to continue the cycle |
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Term
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Definition
-Pressurized Water Reactor
-core --> enriched uranium with H20 and D20
-D20 --> "heavy water"/deuterium
1. acts as moderator to slow down neutrons to induce more fission
2. acts as heat transfer agent
-control rods --> cadmium metal (as reaction becomes self sustaining) |
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