Chemistry - Ch 6 Flashcards
Electronic structure (of atoms)
arrangements of electrons in atoms
Electromagnetic radiation
carries energy through space; radiant energy; example = visible light
Speed of light
3.00 x 10^8 m/s
Wavelength
distance between two adjacent peaks (or two adjacent troughs)
Frequency
number of complete wavelengths (or cycles) that pass a given point each second
Amplitude
relates to the intensity of the radiation, which is the maximum extent of the oscillation of the wave
Electromagnetic spectrum
various types of electromagnetic radiation arranged in order of increasing wavelength
Hertz
cycles per second (Hz)
Blackbody radiation
the emission of light from hot objects
Photoelectric effect
the emission of electrons from metal surfaces on which light shines; explained by Albert Einstein using Planck’s Quantum Theory
Emission spectra
the emission of light from electronically excited gas atoms
Quantum
“fixed amount”; smallest quantity of energy that can be emitted or absorbed as electromagnetic radiation; named by Max Planck; Energy (E) = h (Planck’s Constant) times nu (v)
Planck’s Constant
6.626 x 10^-34 joule-second (j-s)
Photon
“energy packet” that behaves like a tiny particle; part of the photoelectric effect; Einstein deduced that each photon must have an energy to Planck’s constant times the frequency of light (E = hv)
Work function
certain amount of energy required for an electron to overcome the attractive forces that hold it in the metal
Photochemical reactions
radiation breaks chemical bonds
Monochromatic
radiation composed of a single wavelength
Spectrum
produced from radiation is separated into its different wavelength components
Continuous spectrum
rainbow of colors, containing light of all wavelengths
Line spectrum
a spectrum containing radiation of only specific wavelengths
Rydberg equation
allowed the calculation of the wavelengths of all the spectral lines of hydrogen
Ground state
lowest energy state (n=1) of an atom
Excited state
electron in a higher, less negative orbit
Momentum
product of the mass and velocity of an object
Matter waves
wave characteristics of material particles; coined by De Broglie
Uncertainty Principle
by Heisenberg; dual nature of matter places a fundamental limitation on how precisely we can know both the location and the momentum of any object; limitation becomes important only when we deal with matter at the subatomic level (with masses as small as that of an electron)
Wave functions
series of mathematical functions that describe the electron in an atom
Probability density (electron density)
Psi squared; = square of the wave function; represents the probability that the electron will be found at a particular location
Orbitals
Set of wave functions and corresponding energies
Electron shell
collection of orbitals with the same value of n
Subshell
set of orbitals with the same n and l values
Radial probability function
probability that the electron will be found a certain distance from the nucleus
Node
intermediate point at which a probability function goes to zero
Degenerate
Orbitals with the same energy
Electron spin
intrinsic property of electrons that causes each electron to behave as if it were a tiny sphere spinning on its own axis
Spin Magnetic Quantum Number
quantum number associated with the electron spin; may have values of + 1/2 or -1/2
Pauli Exclusion Principle
No two electrons in an atom can have the same set of four quantum numbers (n, l, ml, & ms)
Electron configuration
the way in which electrons are distributed among the various orbitals of an atom
Hund’s Rule
for degenerate orbitals, the lowest energy is attained when the number of electrons with the same spin is maximized
Core electrons
inner shell electrons
Outer-shell electrons
electrons given the after the noble-gas core
Valence electrons
electrons involved in chemical bonding
Transition elements (transition metals)
4th row of the periodic table; 10 elements wider than two previous rows
Lanthanide elements (rare earth elements)
14 elements corresponding to the filling of the 4f orbitals
Actinide elements
final row of the periodic table; begins by filling the 7s orbitals; most are radioactive, not found in nature
Representative elements (main-group elements)
s block and p block of the periodic table together
F-block metals
below the main portion of the periodic table, two tan rows with 14 columns; valance f orbitals are being filled
