MCAT: General Chemistry Chapter 1 (KAPLAN) Questions and Answers Already Passed

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MCAT: General Chemistry Chapter 1 (KAPLAN) Questions and Answers Already Passed isotopes ✔✔different number of neutrons in atoms, same atomic number but have different mass number -- they exhi ... bit similar chemical properties and are normally labeled by their mass number (carbon 12) except in hydrogens (protium, deuterium, and tritium) mass number ✔✔sum of protons and nucleus in nucleus -- changes with each varying isotope valence electrons ✔✔farthest electrons from the nucleus and because they are so far, they feel the least amount of electrostatic pull from the nucleus and therefore can bond with others (interact with their surrounding environment) -- determine reactivity of an atom most easily removed "active" electrons dominate the chemical behavior of an atom Electron energy levels ✔✔electrons closer to the cell nucleus have lower energy levels, and farther away have higher energy levels which subatomic particle is most important for determining: charge? ✔✔electron which subatomic particle is most important for determining: atomic number? ✔✔proton which subatomic particle is most important for determining: isotope? ✔✔neutron how to determine number of protons ✔✔atomic number atomic weight ✔✔average mass of naturally occurring isotopes mass of one proton ✔✔one amu = 1/12 of the carbon-12 atom (difference between proton and neutron mass is very small, the difference is equal to an electron) half-life correspond with ____ therefore helps determine ____ ✔✔stability, the relative proportions of these different isotopes the relationship between atomic weight, isotopes, and moles ✔✔the atomic weight of carbon is 12 amu, which means the average carbon weighs 12 amu (meaning carbon 12 isotope is extremely more abundant than 13 or 14) and one mole of carbon atoms is equal to 12 grams atomic mass ✔✔nearly equal to mass number (slightly less than the number of protons and neutrons in a nucleus) Ernest Rutherford ✔✔experimental evidence that an atom has a dense positively charged nucleus that one accounts for a small portion of the atom's volume (VOLUME) Max Planck ✔✔developed first quantum theory - energy emitted as electromagnetic radiation for matter comes in discrete bundles called quanta (the energy of a quantum is given by the Planck Relation) Plank Relation ✔✔E=h*f Planck's constant ✔✔h, frequency of the radiation (in Planck's relation) Neils Bohr ✔✔electron traveled in a circular orbit around the central proton nucleus, this centripetal force acting on the electron is from the electrostatic force between positive protons and negative electrons (used the work of Rutherford and Planck) Bohr's use of Planck's constant ✔✔placed restrictions on the angular momentum that drove the pathways of electrons (previously pathways were defined by classic physics) L=(n*h)/2pi because n is the only variable, the angular momentum can only change in discrete amounts respective to the quantum number what are the similarities between quantized angular momentum and Planck's concept of quantized energy ✔✔There is only discrete energy levels possible, energy isn't infinite Bohr related the permitted angular momentum values to the energy of the electron to obtain: ✔✔the energy of the electron changes in discrete amounts with respect to the quantum number (im sure the actual equation is not important to memorize E=-Rn/n^2) what is the energy of the electron equation saying? (E=-Rn/n^2) ✔✔as the energy of an electron increases, aka becomes less negative, the farther out from the nucleus it will be located (larger n) important point: while magnitude of the fra [Show More]

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