Book: Ch. 7 Flashcards
Define: electromagnetic radiation
Visible light, x-rays, radio waves, and microwaves are examples. Basically photons.
Define: frequency (ν)
Number of complete waves or cycles that pass a given point per second, usually expressed by the unit s⁻¹ or hertz (Hz)
Define: wavelength (λ)
Distance between any point on a wave and the corresponding point on the next crest or trough of the wave. The distance the wave travels during one cycle. Usually measured in nm.
Define: speed of light (c)
c = νλ = 3.00×10⁸ m/s
Define: amplitude
Height of the crest. For electromagnetic waves, this corresponds to the intensity of the radiation.
Define: electromagnetic spectrum
The types of electromagnetic radiation arranged in order of increasing wavelength.
Define: ultraviolet radiation (UV)
Spectrum of electromagnetic radiation to the left of visible light on the spectrum.
Define: infrared radiation (IR)
Spectrum of electromagnetic radiation to the right of visible light on the spectrum.
Define: refraction
When a wave passes from one medium to another, it refracts: it changes direction and the wave continues at a different angle.
Define: diffraction
When a wave strikes the edge of an object, it bends around it. This is diffraction.
What is the equation for the energy of a photon?
E = nhν, where n is a quantum number taking values of positive integers, and h is Planck’s constant.
Define: Planck’s constant
h = 6.626×10⁻³⁴ [J s]
What is the relationship between the change in energy of a photon and the properties of light is emits?
∆E atom = E emitted radiation = hν = hc/λ
Define: photoelectric effect
A phenomenon explained by Einstein with the introduction of the photon theory of light.
Define: photon
A single particle of light.
What is the energy of a photon?
E photon = hv = ∆E atom
What is the Rydberg equation?
1/λ = R(1/n₁² - 1/n₂²)
Define: stationary states
The H atom has only certain energy levels. Bohr called these the stationary states.
How is the energy level between two different states of the H atom found?
∆E = -2.18×10⁻¹⁸ (1/n_f² - 1/n_i²)
Define: de Broglie wavelength
Equation λ = h/mu, where u is speed of the object. Basically gives the wavelength of an object, under the assumption that matter behaves like a wave.
Define: uncertainty principle
It is impossible to know simultaneously the position and momentum of a particle, so m∆x∆u ≥ h/4π
Define: principal quantum number (n)
A positive integer giving the relative size of the orbital an electron has as well as its energy level.
Define: angular momentum quantum number (l)
An integer from 0 to n - 1. n sets the limit on what values l can take. l is related to the shape of the orbital.
Define: magnetic quantum number (m_l)
An integer from -l through 0 to l. Number of m_l values = 2l+1 = number of orbitals for a given l. Prescribes three-dimensional orientation of the orbital in the space around the nucleus.
Define: levels and sublevels for atoms
Level: aka shells of an atom. Given by n value.
Sublevels: subshells. Given by the l value. l = 0 is s sublevel, 1 is p, 2 is d, 3 is f.
