Chemistry Exam II
Terms
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- Anode
- A positively charged electrode.
- Cathode
- A negatively charged electrode
- Cathode Ray
- A stream of electrons emitted by the cathode in electrical discharge tubes.
- Electron
- A negatively charged particle of an atom
- Proton
- A positively charged particle of an atom
- Nucleus
- the center of an atom made of protons and neutrons.
- Isotopes
- different forms of an element that differ in the number of neutrons found in the nucleus
- AMU
- Atomic Mass Unit
- Atomic weight
- The average mass of an atom of an element
- Atomic number
- the number of protons in an atom's nucleus & its number of electrons.
- Mass number
- The sum of an atom's protons and neutrons within its nucleus.
- Ion
- An atom that has become electrically charged due to a gain or loss of electrons
- Frequency
- The number of times per second a wave goes through a complete upward and downward cycle.
- Wave length
- The distance between two identical successive points on a wave
- Orbital
- A map that describes the region in space where an electron can be found.
- Pluker
- German scientist - experimented with cathode ray tubes. Placed a magnet next to a cathode ray tube and observed a glow effect from cathode rays . Concluded with discovery of electron.
- Goldstein
- German scientist - experimented with cathode ray tubes. Observed some rays pass through holes in a cathode & these were called positively charged anode rays. Concluded with discovery of proton.
- Roentgen
- German scientist - experimented with UV radiation within cathode ray tubes. Observed that he could see inside of solid objects placed between a screen made of BaPt(CN)4 and an activated cathode-ray tube . He concluded with the discovery of the x-ray.
- Rutterford
- British Scientist - studied absorption of radioactivity by thin sheets of metal foil. Observed the effects of three forms of radiation on foil. One was almost immediately absorbed by metal foil, the second passed through 100 times more foil before absorption, and the third passed through several centimeters of lead. He concluded with the discovery of alpha, beta and gamma-ray radiation.
- Rutterford gold foil experiment
- Discovered a few alpha particles bounce back off gold foil. Concluded that an atom has a small nucleus made of protons.
- Mosely
- English Scientist - studied x-rays given off by cathode-ray tubes. Observed that frequencies of x-rays depend on the metal used. Concluded an element's atomic number and positive charge on its nucleus are equal.
- Calculate Atomic Weight
- first, convert all of your element's isotropic abundances into decimals multiply each form's Mass by its decimal form isotropic abundance. Add up all of the answers to get the Atomic Weight.
- Calculate Frequency
- Frequency = Speed of light / Wave length
- Oxidation state
- The most stable amount of ions an atom can form.