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71 Cards in this Set
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Electromagnetic (EM) radiation

Energy transmitted by wave propagation of electric and magnetic fields


Wavelength

Distance wave travels in one cycle


Frequency

Number of cycles per unit time


Velocity

Distance per unit time


Diffraction

Dispersion (separation) of different wavelengths of light by reflection from a grooved surface


Diffraction: constructive interference

waves interact inphase (amplitude increase)


Diffraction: destructive interference

waves interact out of phase (amplitude reduction)


Diffraction: grooved surface (grating)

results in interference between reflected wavelenths


Refraction

dispersion of light as it passes through a different medium (material)


Refraction: velocity of light

reduced by interaction with atoms and molecules matter


Refraction: degree of refraction

dependent of frequency of light


Spectrum

band of different wavelenths from dispersed EM radiation


continuous spectrum

contains approximately all wavelengths in a given range


discontinuous specrum

contains small number of discrete wavelength


Atomic line spectrum

discontinuous spectrum produced by excited atoms


atomic emission

gas phase atoms emit light when thermally or electrically excited


line spectra

wavelenghts specific to particular elements


Balmer

fit oberseved wavelengths (visible) of Hatom line spectrum to mathematical equation


Plank

atoms emit/absorb only discrete amounts (quanta) of energy


Photoelectric effect

ejection of electrons when photons strike a metal surface


light intensity

number of photons per unit time (no effect unless above threshold frequency)


Bohr

Developed model to explain line spectrum of the hydrogen atom


atomic energy levels

fixed orbits of electrons around the nucleus (discrete allowed states)


photon absorbtion

e moves to higher orbit


photon emission

e moves to lower orbit


line spectra

discrete wavelengths correspond to electrons changing orbits (photon emission)


Why is the Bohr model limited and inaccurate

only predicts spectra for oneelectron systems
electrons do NOT move in fixed orbits 

Energy states of an ato (Bohr model)

ground state=lowest energy level
excited state=energy level higher than ground state 

Z

numlear charge (atomic #)


n

energy level (integer for allowed state)


Photon energy

difference in energy between state (consevation of energy)


Quantum mechanics

application of wave properties to matter


Waveparticle duality

light exhibits both wave and particle properties and behavior


de Broglie

matter exhibits both partible and wave properties


Mater waves

waves associated with material particles of nuclear or atomic dimensions


Standing waves

crests and troughs occur at fixes positions (amplitude at fixed endpoints)


nodes

points in wave with constant zero amplitude (no displacement during wave oscillation)


wavefunction

mathematical function describing wave motion of a particle


schrodinger equation

extracts physically relevant information from allowed wavefunctions


principal quantum #(n)

describes average radial distance of electron from nucleus
n=positive, non zero integer 

Orbital angular momentum quantum # (l)

determines angular distribution fo orbital


energy sublevel(subshell)

subset of principal energy level


sublevel notation

n value followed by sublevel name


Magnetic quantum # (ml)

determines orientation of electron orbital


# values for ml

# electron orbitals within particular sublevel


Orbital energies (oneelectron system)

defined by principal quantum number (n)
sublevels=degenerate (same energy) within principal level for oneelectron system 

Electron charge density

probability density of finding e at a point


probability density distribution

three dimensional "shape" or orbital


s orbital

greatest electron density at the nucleus; spherical shape


p orbital

no electron density at the nucleus; nonspherical shape


d orbital

no electron density at nucleus; various (nonspherical) shapes


orbital energies

affected by charge interactions within atom


nuclear charge (Z)

positive charge of nucleus (attracts negative electrons)


Electron shielding

one electron shields another electron from the full nuclear charge


effective nuclear charge

nuclear charge actually experienced by electron


Electron penetration

ability of an electron to approach nucleus (depends on l)


radial probability distribution

probability of finding e at a certain radius from nucleus


orbital energies (multielectron system)

sublevel energies altered by electron penetration and shielding
one electron system=no electonelectron relulsionsublevel energies degenerate (same energy) 

multielectron system

sublevel energies separated due to electron penetrarion and shielding


Electron spin

movement of electron on tis ezis generates magnetic field


electron spin quantum number (ms)

indicates direction of electron spin


electron configuration

designation of how electrons are distributed in orbitals


orbital filling order

in terms of increasing orbital energy


pauli exclusion principle

each electron must have a unique set of quantum numbers


Hund's rule

if degenerate orbitals are avaiable electronelectron repulsion is minimized


Aufbau method

distribute electrons to minimize energy


periodic table

indicates filling order in terms of increasing orbital energy


principle quantum # (n)

related to period (row) number


abbreviated notation

noble gas symbol used to represent core electrons


superscripts

indicate number of electrons in each orbital


dorbitals

lower energy associated with half filled and filled sublevels
