Chapter 7 Vocab Flashcards
(40 cards)
Electromagnetic radiation (also electromagnetic energy or radiant energy)
Oscillating, perpendicular electric and magnetic fields moving simultaneously through space as waves and manifested as visible light, x-rays, microwaves, radio waves, and so on.
Frequency (ν)
The number of complete waves, or cycles, that pass a given point per second, expressed in units of 1/second, or s^-1 [also called hertz (Hz)]; related inversely to wavelength.
Wavelength (λ)
The distance between any point on a wave and the corresponding point on the next wave, that is, the distance a wave travels during one cycle.
Speed of light (c)
A fundamental constant giving the speed at which electromagnetic radiation travels in a vacuum; c = 2.99792458 x 10^8 m/s.
Amplitude
The height of the crest (or depth of the trough) of a wave; related to the intensity of the energy (brightness of the light).
Electromagnetic spectrum
The continuum of radiant energy arranged in order of increasing wavelength.
Ultraviolet (UV)
Radiation in the region of the electromagnetic spectrum between the visible and the x-ray regions.
Infrared (IR)
The region of the electromagnetic spectrum between the microwave and visible regions.
Refraction
A phenomenon in which a wave changes its speed and therefore its direction as it passes through a phase boundary into a different medium.
Diffraction
The phenomenon in which a wave striking the edge of an object bends around it. A wave passing through a slit as wide as its wavelength forms a circular wave.
Quantum number
A number that specifies a property of an orbital or an electron.
Planck’s constant (h)
A proportionality constant relation the energy and frequency of a photon, equal to 6.62607015 x 10^-34 J⋅s.
Quantum
A packet of energy equal to hν. The smallest quantity of energy that can be emitted or absorbed.
Photoelectric effect
The observation that, when monochromatic light of sufficient frequency shines on a metal, an electric current is produced.
Photon
A quantum of electromagnetic radiation.
Line spectrum
A series of separated lines of different colors representing photons whose wavelengths are characteristic of an element (see also emission spectrum).
Stationary state
In the Bohr model, one of the allowable energy levels of the atom in which it does not release or absorb energy.
Ground state
The electron configuration of an atom (or ion or molecule) that is lowest in energy.
Excited state
Any electron configuration of an atom (or ion or molecule) others than the lowest energy (ground) state.
de Broglie wavelength
The wavelength of a moving particle obtained from the de Broglie equation: λ = h/mu.
Wave-particle duality
The principle stating that both matter and energy have wavelike and particle-like properties.
Uncertainty principle
The principle stated by Heisenberg that it is impossible to know simultaneously the exact position and velocity of a particle; the principle becomes important only for particles of very small mass.
Quantum mechanics
The branch of physics that examines the wave nature of objects on the atomic scale.
Schrödinger equation
An equation that describes how the electron matter-wave changes in space around the nucleus. Solutions of the equation provide energy states associated with the atomic orbitals.
