Chapter 7 Flashcards
absorption spectrum
the spectrum produced when atoms absorb specific wavelengths of incoming light and become excited from lower to higher energy levels
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)
angular momentum quantum number (l)
an integer from 0 to n − 1 that is related to the shape of an atomic orbital
atomic orbital
the wave function of an electron in an atom. the term is used qualitatively to mean the region of space in which there is a high probability of finding the electron
d orbital
an atomic orbital with l = 2
de Broglie wavelength
the wavelength of a moving particle obtained from the de Broglie equation: λ = h/mu
diffraction
he 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
electromagnetic radiation
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
electromagnetic spectrum
the continuum of radiant energy arranged in order of increasing wavelength
electron cloud depiction
an imaginary representation of an electron’s rapidly changing position around the nucleus over time
electron density diagram
the pictorial representation for a given energy sublevel of the quantity ψ2 (the probability density of the electron lying within a particular tiny volume) as a function of r (distance from the nucleus)
emission spectrum
the line spectrum produced when excited atoms return to lower energy levels and emit photons characteristic of the element
excited state
any electron configuration of an atom (or ion or molecule) other than the lowest energy (ground) state
f orbital
an atomic orbital with l = 3
flame test
a procedure for identifying the presence of metal ions in which a granule of a compound or a drop of its solution is placed in a flame to observe a characteristic color
frequency
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
ground state
the electron configuration of an atom (or ion or molecule) that is lowest in energy
infrared (IR)
the region of the electromagnetic spectrum between the microwave and visible regions
level (shell)
a specific energy state of an atom given by the principal quantum number n
line spectrum
a series of separated lines of different colors representing photons whose wavelengths are characteristic of an element
magnetic quantum number
an integer from −l through 0 to +l that specifies the orientation of an atomic orbital in the three-dimensional space about the nucleus
node
a region of an orbital where the probability of finding the electron is zero
p orbital
an atomic orbital with l = 1
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
Planck’s constant (h)
a proportionality constant relating the energy and frequency of a photon, equal to 6.626 × 10−34 J·s
principal quantum number (n)
a positive integer that specifies the energy and relative size of an atomic orbital; a number that specifies an energy level in an atom
probability contour
a shape that defines the volume around an atomic nucleus within which an electron spends a given percentage of its time
quantum
a packet of energy equal to hν. the smallest quantity of energy that can be emitted or absorbed
quantum mechanics
the branch of physics that examines the wave nature of objects on the atomic scale
quantum number
a number that specifies a property of an orbital or an electron
radial probability distribution plot
the graphic depiction of the total probability distribution (sum of ψ2) of an electron in the region near the nucleus
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
s orbital
an atomic orbital with l = 0
Schrodinger 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
spectrometry
any instrumental technique that uses a portion of the electromagnetic spectrum to measure the atomic and molecular energy levels of a substance
speed of light (c)
a fundamental constant giving the speed at which electromagnetic radiation travels in a vacuum: c = 2.99792458 × 108 m/s
stationary state
in the Bohr model, one of the allowable energy levels of the atom in which it does not release or absorb energy
sublevel (subshell)
an energy substate of an atom within a level. given by the n and l values, the sublevel designates the size and shape of the atomic orbitals
ultraviolet (UV)
radiation in the region of the electromagnetic spectrum between the visible and the x-ray regions
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
wavelength
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
wave-particle duality
the principle stating that both matter and energy have wavelike and particle-like properties
