ACS EXAM Review 2024 Study Questions and Answers

Rutherford's Gold Foil Experiment - proposed that atoms consist of a tiny, massive, positive nucleus surrounded by electrons nucleus - contains all the positive charge and nearly all the mass of the atom James Chadwick - discovered the neutron cathode rays - move from negative electrode to positive electrode (like electrons in a voltaic cell) Thompson's Cathode Ray Experiment - discovery of the electron (also the discovery that atoms are divisible into smaller particles) Millikin's oil drop experiment - determined the charge of the electron through highest grade clock oil and electrons from X-ray that clung to positive charged oil drops- determined that electrons are some whole value of charge (Faraday constant) Thompson's plum pudding model - model of a spherical atom composed of diffuse positively charged matter in which electrons are embedded like raisins in plum pudding atomic number - number of protons (Z) mass number - number of protons and neutrons (nucleons) (A) isotopes - same element with different numbers of neutrons mass spectrometry - a method for measuring the relative masses and abundances of atomic scale particles very precisely empirical formula - shows relative number of atoms in a compound molecular formula - shows the actual number of atoms of each element in a molecule of compound aufbau principle - the rule that electrons occupy the orbitals of lowest energy first quantum mechanics - mechanics applied to the atomic and nuclear level and dealing with photons and other quanta that show both wave and particle behavior Heisenburg's uncertainty principle - the statement that, due to the laws of quantum mechanics, it is impossible to simultaneously exactly measure a particle's position and momentum or to exactly measure a particle's energy for a finite amount of time. electron energy - The strength of attachment of an electron to the nucleus of an atom; the closer and electron to the nucleus, the higher the electron binding energy. quantum numbers - the four numbers that define each particular electron of an atom. The Principle Quantum Number (n) describes the electrons' energy and distance from the nucleus. The Angular Momentum Quantum Number (l) describes the shape of the orbital in which the electron resides. The Magnetic Quantum Number (m) describes the orientation of the orbital in space. The Spin Quantum Number (s) describes whether the spin of the electron is positive or negative. photon - packet of energy electromagnetic radiation - A form of energy exhibiting wavelike behavior as it travels through space; can be described by wavelength, frequency, amplitude, and speed. radial probability distributions - a graph in which the total probability of finding the electron in each spherical shell is plotted versus the distance from the nucleus isoelectronic - same number of electrons alpha particle - ... beta particle - ... gamma ray - ... group 1 - alkali metals group 2 - alkaline earth metals group 7 - halogens group 8 - noble gases electromagnetic spectrum (decreasing energy) - x-ray, uv-ray, visible light, infrared light, microwaves, tv, radio waves higher photon energy - higher frequencies (∨) and shorter wavelengths (λ) speed of light (c) - 3.00 x 10⁸ ms⁻¹, maximum speed of any and all motion; electromagnetic waves travel at this speed