Chapter 7: Electronic Structure Flashcards
Rutherford’s model did not address
how the electrons occupied the space around the nucleus
initially, it was assumed that electrons held … about the nucleus, leading to the … model of the atom
fixed orbits; planetary
under certain conditions, atoms and molecules emit and absorb energy in the form of
light
in the late 19th century, physicists knew that light could be described as
waves
waves are … in nature: they…
periodic; repeat at regular intervals of both time and distance
any wave is described by its
wavelength, frequency, and amplitude
wavelength (λ, …) is the …
lambda; distance between one peak to the next
in SI system, wavelength is measured in
meters
frequency (v, ..) is the number of …
nu; waves that pass a fixed point in 1 second
the SI unit for frequency si … and is called ..
s^-1; hertz (Hz)
amplitude is the … of a wave
maximum height
height of a wave varies between
+Amax and -Amax
light waves are called… because they consist of …, which are perpendicular to … and to the direction of …
electromagnetic radiation; oscillating electric and magnetic fields; each other; propagation;
the speed at which a wave travels is the product of its
wavelength and frequency
the periodic nature of wave motion is not always
easily seen
the experimentally measured speed of light shows that all electromagnetic radiation travels at the
same speed in a vacuum, no matter what its wavelength
the speed of light in a vacuum is one of the fundamental constants of nature:
3.00 x 10^8 m/s
c=
λv
the amplitude is the vertical …
displacement from the undisturbed medium
the length of time that it takes for one complete wave to pass a point is
deltat
wavelength and frequency are
inversely proportional
the human eye can detect only a very small part of the electromagnetic range, called
visible light
visible light includes wavelengths from … to … nm
400; 700
order of colors for visible spectrum:
VIBGYOR
shorter wavelengths are
higher in energy
amplitude indicates the .. of light source
brightness
gamma and x rays are the
shortest wavelengths (highest in energy)
radio and microwaves are the
longest wavelengths (smallest in energy)
at temperatures greater than absolute zero, matter emits …., and the emission is referred to as a …
electromagnetic radiation of all wavelengths; continuum
not all wavelengths of light are emitted with
equal intensity
the distribution of the intensity of different wavelengths changes with
temperature
in 1900, max planck proposed an explanation of the wavelengths emitted by … that was based on an assumption that violated the classical models of physics
heated objects
planck assumed that the particles of matter in the heated objects were …., and that the amount of energy the particles had was proportional to the …
vibrating back and forth; frequency at which the particles vibrated
planck’s equation
E= hv
h, …., is =
planck’s constant; 6.626 x 10^-34 J * s
because the energy of the vibrating particle has a specific energy, the energy is considered to be
quantized
Einstein applied planck’s equation to … and proposed that light behaves as a …. whose value is directly proportional to the …
light; particle of energy; frequency of the light
Einstein essentially proposed that the energy of light was …, meaning that it could only be a …
quantized; certain amount
photoelectric effect is the process in which electrons are ….
ejected from solid metal when it is exposed to light
each metal has a characteristic …., that is necessary before any …
minimum frequency; electrons are emitted
as the frequency of light increases from the minimum, the kinetic energy of the ejected electrons
alos increases
more intense light does not increase the ….., but it does increase the …
kinetic energy of the electrons; number of electrons emitted
Einstein suggested that light not only had wave properties, but could be viewed as a stream of tiny particles, referred to as
photons
a … with an energy of hv must provide enough energy to …
SINGLE photon; eject an electron
some of the energy, hv0, must be used to overcome the ….
attraction the solid has for the electrons
equation with hvs and ke
hv = hv0 + KE
one photon of light can eject
one electron
increasing the intensity of the light source produces more …, because the number of photons is …
ejected electrons of the same KE; proportional to the intensity
if the energy of the absorbed photon is less than hv0, even with an increased intensity it will only
heat the metal
Einstein’s explanation in conjunction with planck’s theory suggested that each …. was carried by a …
quantum of energy; particle of light or a photon
in the interpretation of the photoelectric effect, electromagnetic radiation is treated as … instead of ..
particles of light (photons); waves
when energy in the form of heat or an electric discharge is added to a sample of gaseous atoms in a process called …, the atoms can emit some of the …
excitation; added energy as light
spectrum: the … of the light as a function of …
intensity; wavelength
a heated solid produces a …., one in which all … are present
continuous spectrum; wavelengths
the light emitted by excited atoms is called a … because it contains light only at …
line spectrum; specific wavelengths
each element produces a line spectrum that is … and different from the spectrum of …
characteristic of that element; any other element
wavelengths of all lines in the spectrums given by the
Rydberg equation
Rydberg equation:
1/λ=R_H (1/(n_1^2 )-1/(n_2^2 ))
n1 and n2 are positive integers with n1 …
< n2
Rh, called the .., has the value of …
Rydberg constant; 1.097 x10^7 m^-1
they hydrogen atom spectrum consists of series of lines that are named after those who discovered them:
Lyman (n1 = 1) Balmer (n1 = 2) Paschen (n1 = 3) Brackett (n1 = 4) Pfund (n1 = 5)
The Rydberg equation accurately predicts the wavelengths ofall observed lines in the
spectrum of hydrogen atoms
the discrete line spectra of atoms suggested that electrons exist in
only certain allowed energy levels
niels bohr proposed a model for the … that accounted for the …
hydrogen atom; observed spectrum of hydrogen
bohr assumed that the electron moved in … around the nucleus
circular orbits
bohr assumed that the electron could have only certain values of
angular momentum
angular momentum:
momentum of a mass moving in a circle
bohr also found that the allowed … and …. are also quantized
radii; energies
En=
(-(2π^2me^4)/h^2)*1/n^2 = -B/ n^2