Chemistry Praxis Review Questions and Answers

Schrodinger (1925) Continued upon Bohr's findings to determine where electrons are typically found. Heisenberg (1927) Created the heisenberg uncertainty principle because you never can predict where the electron is. (Breaking Bad) De Broglie (1924) Electrons act like waves around the atom. Niels Bohr (Bohrbit) (1913) Electrons can orbit the nucleus in certain special orbits at different energy levels around the nucleus. Earnest Rutherford (foil) (1910) Fired beam of alpha particles at thin gold leaf foil and determined atoms have nucleus; the particles get deflected and neutral neutrons stay. Max Planck Developed Quantum theory and found energy is transferred by radiation. E = hv h = constant 6.6260 x 10^-34 J.J. Thomson (1897) Discovered positive atoms with negative electrons, but didn't know about nucleus. Made Plum pudding Model. Dalton's Modern Atomic Theory j1. all matter is composed of atoms. 2. atoms of a given element are identical in size, mass and other properties-(disproven); atoms of different elements differ in same factors. 3. atoms cannot be subdivided, created, or destroyed.-(disproven) 4. atoms combine to form compounds. 5. in chemical reactions, atoms are combined, separated, or rearranged. John Dalton () Created Modern Atomic Theory detailing original thoughts of the atom; didn't know about neutrons or electrons. When Gibbs (G) = 0 The reaction is at equilibrium (reversible) Gibbs Free Energy (G) G = H - TS H = change in enthalpy T = temp. change (kelvin) S = change in entropy