CEM 141 MSU Exam 2 Questions with 100% Correct Answers | Verified

Lights acts as what? - Answer-Particle and wave. Wavelength - Answer-The distance (m) of waves from peak to peak. Short: x-ray (red), long: infrared (blue) Short - higher energy Long - lower energy Frequency (V) - Answer-The number of wavefronts per second. Highest: x-ray Velocity of Light - Answer-C = 3.00 X 10^8 = wavelength X frequency Amplitude - Answer-The intensity, height of peaks of waves. Highest: blue light Energy of Wave (J) - Answer-Increases as frequency increases and as wavelength decreases. Highest: xray Range of Wavelengths - Answer-10^-16 - 10^8 = 24. Only a third are visible Black Body Radiation - Answer-When a mass is heated it emits a type of EM radiation, at very high temps the mass becomes "white hot" because all wavelengths of visible light become equally intense Photoelectric Effect - Answer-Metals emit electrons when electromagnetic radiation shines on the surface, light is transfers energy to the electrons at the metal's surface where it's transformed into KE that gives the electrons enough energy to leave the atom Depends on frequency not intensity How many electrons are emitted if the light is below it's threshold frequency no matter the intensity? - Answer-None.What increases the number of electrons to be emitted by the photoelectric effect? - Answer-Intensity. A particle that transfers light energy with a definable energy, emits one electron energy of = h (6.626 x 10^-34 J) - Answer-Photon. Energy of light equation? - Answer-E = hV. h - Answer-Planck's constant, the energy of a photon. What happens to the energy when there is a short wavelength? - Answer-High energy. Light from the sun (white light) can be separated by a prism to create this, only a small part of the full EM spectrum? - Answer-Visible Spectrum. Atomic Emission Spectrum - Answer-Spectrum that emits photons, energy diagram: electron goes down energy levels. Atomic Absorption Spectrum - Answer-Spectrum that absorbs photons, energy diagram: electrons goes up in energy levels. Heisenberg Uncertainty Principle - Answer-Principle states that we can't accurately measure both the position and the energy of a small particle (electron) Bohr's model did - why its wrong. Schrodinger's Wave Equation - Answer-Treated electron as waves derived by mathematical descriptions of energies. Psi = wave function of an electron Psi^2 = probability of finding an electron.Atomic Orbitals - Answer-Regions of space where electrons with a particular quantized energy have a high probability of being found, described by quantum numbers. What are the quantum numbers? - Answer-n, l, ml, and ms. What does quantum number "n" mean? - Answer-Determines the energy of the electron and identifies its shell. What does quantum number "l" mean? - Answer-Identifies the type of orbital (s,p,d) and subshell = 0 - n-1. What does quantum number "ml" mean? - Answer-Specifies a particular orbital within a subshell = -l - +l (2l + 1 possible values) tells us how many s,p,d orbitals are found in each sub shell. What does quantum number "ms" mean? - Answer-Describes the spin of the electron in each orbital = +1/2 or -1/2 (only 2 e- in each orbital, each one has either + spin or - spin). Aufbau Principle - Answer-Principle that electrons occupy the lowest level orbitals first. Hund's Rule - Answer-Rule that electrons occupy orbitals of the same energy singly until they have to pair up. Core Electrons - Answer-Low in energy electrons that are close to the nucleus within the closed shell, doesn't participate in reactions. Valence Electrons - Answer-High in energy electrons that are outside of closed shell and determine reactivity.Atomic Radius - Answer-Half the distance between two nuclei, increases down a group, decreases across a row Depends on attraction of protons and electrons and repulsions of electrons Represents state where forces between attraction and repulsion in an atom are equal. Effective Nuclear Charge - Answer-= Protons - Core Electrons Increases across the row, decreases down the group (as atomic radius decreases) How tight the electrons are being attracted to the nucleus