OpenStax Chapter 6 Key Term Flashcards
wave
oscillation or periodic movement that can transport energy from one point in space to another
wavelength
distance from peak to peak or trough to trough
frequency
the number of wave cycles (one complete wavelength) that can pass a given point in space in a given amount of time s^-1
amplitude
maximum displacement from equilibrium
hertz
unit for frequency
electromagnetic spectrum
energy and frequency have a direct relationship
frequency and wavelength have a indirect relationship
standing waves
constrained within a region in space
play important role in understanding electronic structure of atoms
have an integer number, n, of half wavelengths between endpoints
quantization
only discrete values for a more general set of continuous values of some properties are observed
nodes
points between the two end points that are not in motion
n-1 nodes, where n is the number of half wavelengths
energy increases with the amount of nodes
blackbody radiation
sunlight consists of a range of broadly distributed wavelengths that form a continuous spectrum
blackbody - convenient, ideal emitter that approximates the behavior of many materials when heated
ultraviolet catastrophe
classical prediction that the intensity of the radiation radiated by a blackbody would increase as the wavelength decreased
photoelectric effect
electrons can be emitted from surface of metal when it is hit with light that has a frequency greater than the threshold
the kinetic energy of the emitted electron depends on the frequency of the light
even at lower intensity, light of the appropriate frequency can eject an electron
photoelectric effect (conc.)
light consists of radiation or quanta or packets of EM radiation with energy proportional to frequency of light
the greater the frequency of the photon, the greater the KE of the emitted electron
light has wave and particle nature
photon
particle of light
wave-particle duality
light has wave and particle behavior
line spectrum
heated solid, liquids, and condensed gases emit light of a range of frequencies to produce a continuous spectrum
heated gases emit light at discrete wavelengths; each emission line consists of a single wavelength
Balmer
derived an equation that related the four visible lines in the hydrogen emission spectrum to whole numbers
n_f = 2
Rydberg
developed an equation to reproduce all of the lines in the hydrogen spectrum
Bohr’s model of the atom
assumed that electrons would not emit or absorb energy unless it moved from one level to another
energy emitted or absorbed would reflect the energy difference between levels
quantization of energy
rearranges the Rydberg equation/derived an equation for the energy of an electron in hydrogen-like atoms and ions
ground state of the electron
lowest energy state of the electron
excited state of the electron
higher energy states of the electrons
deBroglie wavelength
extended the wave particle duality of light to material particles
wavelength = h/p
Bohr’s idea only applies if electrons are considered circular standing waves
2pir=nlambda
Davisson and Germer
electrons can behave as waves
Heisenberg Uncertainty Principle
it is impossible to determine simultaneously and exactly the momentum and the position of a particle
Schrodinger
described electrons as wavefunctions
three-dimensional stationary waves
reproduced Bohr’s expression for energy and the Rydberg formula
Max Born
electrons are still particles
waves are not physical waves but complex probability molecules
the square of the magnitude of a wavefunction describes the probability of a particle being near a location in space
wavefunctions can be used to determine the distribution of electron density with respect to the nucleus
principal quantum number
the quantum number on which the energy of the electron principally depends on
determines the size of the shell and the distance from the nucleus
angular momentum quantum number
specifies the subshell and the shape of the orbital
0 = s
1 = p
2 = d
3 = f
magnetic quantum number
specifies the orbital’s orientation in space
adopts values: -l…0…+l
spin quantum number
specifies the spin of the electron
ms = +1/2 or -1/2
atomic radius
increases down a group (more energy levels)
decreases across a period (valence electrons being added to the same energy level while proton number increases makes nucleus pull electrons closer)
ionization energy
energy that is required to remove an electron from an atom
decreases down a group (added energy levels makes electrons easier to remove since there is more shielding)
increases across a period (nucleus pulling electrons closer together makes it harder to remove them)
electron affinity
energy change associated with added an electron to a gaseous atom
- = wants to accept an electron
+ = does not want to accept an electron
B and O exceptions to IE
B: 2s subshell has a higher effective nuclear charge since there is a possibility of the electrons being found near the nucleus, so the 2p1 electron is easier to remove
O: half-filled subshell has some stability associated with it, pairing energy - energetic cost associated with adding an electron to a pre-existing orbital with an electron