ch 6 Flashcards
electromagnetic radiation
is characterized by wavelenght and frequency
highest energy rays
gamma rays
lowest energy rays
radiowaves
light acts as
waves
c stands for
speed of light
h stands for
planks constant
what is the value of c
2.998x10^8 m/s
what does R stand for
Rydberg constant
Broglies equation
λ = h/mv, where λ is wavelength, h is Planck’s constant, m is the mass of a particle, moving at a velocity
What is a wavelenght and how is it measured?
is defined as the distance between a given point on a wave and the corresponding point in the next cycle of the wave; it is often measured as the distance between successive crests or high points of a wave
Frequency symbol and what is it
Frequency, symbolized by the Greek letter (ν), refers to the number of waves that pass a given point in some unit of time, usually per second.
What is the unit for frequency
The unit for frequency, written either as s−1 or 1/s and standing for 1 oscillation per second, is called a hertz
equation to relate c (speed of light) to wavelenght to v (frequency)
c(m/s)= λ(m) x v(1/s)
what is the speed of light in km/h?
(1.079×109 km/h)
Order of electromagnetic rays from highest to lowest
Electromagnetic radiation has a wide spectrum, including gamma y-rays, X-rays, UV rays, visible light, IR radiation, microwaves, and radio waves (FM and AM) and long radio waves.
Energy increases from
microwaves (lowest energy) to y rays. With y rays having the highest energy.
formula for energy
E=hc/λ=hv
Formula for wavelenght (debroglies)
λ=h/mv
m is mass in kg
v is velocity in m/s
h is plancks constant
wavelenght is in meters
When theres a large wavelenght what happens to energy and speed
As wavelenght increases, velocity decreases and energy is low
What happens to energy and velocity when wavelength becomes smaller and smaller
Energy increases and speed increases
What is the wavelength of visible light
From 380 nm for violet end to 750 nm to red end
What is the acronym for visible light
ROYGBIV
RED HIGHEST WAVELENGTH
ORANGE
YELLOW
GREEN
BLUE
INDIGO
VIOLET LOWEST WAVELENGTH
How is a photon of light created?
When an electron changes from one atomic orbital to another, the electron’s energy changes. When the electron changes from an orbital with high energy to a lower energy state, a photon of light is created.
Rydberg equation to find spectral lines of h
Change in E (nm)= -Rhc (1/nf^2 - 1/ni^2)
λ is the wavelength of the photon
R = Rydberg’s constant
c=speed of light
h=plancks constant
ni and nf are integers where nf > ni
What is diffraction
Scattering of waves by regular array of objects
Describe absorption for an atom
An atom changes from a ground state to an excited state by taking on energy from its surroundings in a process called absorption (RELAX). The electron absorbs the energy and jumps to a higher energy level.
Describe emission for atoms
Emission (EXCITE): the electron returns to the ground state by releasing the extra energy it absorbed. (from high to low)
what is descalation
Excited to ground level
When is electromagnetic radiation emitted
If a piece of metal is heated to a high temperature, electromagnetic radiation is emitted with wavelengths that depend on temperature
Color at different temperatures
At lower temperatures, the color is a dull red. As the temperature increases, the red color brightens, and at even higher temperatures a brilliant white light is emitted.
Describe the ultraviolet catastrophe
Theories available at the time predicted that, as a solid is heated, the intensity should increase continuously with decreasing wavelength, instead of reaching a maximum and then declining as is actually observed. This perplexing situation became known as the ultraviolet catastrophe because predictions failed in the ultraviolet region.
What is the explanation for the ultraviolet catastrophe
The emitted electromagnetic radiation originated in vibrating atoms (called oscillators) in the heated object. Max proposed that each oscillator had a fundamental frequency (ν) of oscillation and that these oscillators could only oscillate at either this frequency or whole-number multiples of it (nν). Because of this, the emitted radiation could have only certain energies, given by the equationE=nhν
Who offered an explanation for the ultraviolet catastrophe
Max Planck (1858–1947), offered an explanation for the ultraviolet catastrophe:
What did planck propose?
He proposed that energy is quantized
What is quantization
That only certain energies are allowed
Examples of electromagnetic radiation
Visible light, microwaves, television and radio signals, x-rays, and other forms of radiation are now called electromagnetic radiation
Frequency
Frequency, symbolized by the Greek letter (ν), refers to the number of waves that pass a given point in some unit of time, usually per second. The unit for frequency, written either as s−1 or 1/s and standing for 1 oscillation per second, is called a hertz
speed of light formula
c (m/s)= wavelegth(m) x frequency (1/s)
speed of light value
2.998x10^8 m/s
when is electromagnetic radiation emmitted
If a piece of metal is heated to a high temperature, electromagnetic radiation is emit-ted with wavelengths that depend on temperature
colors at different temperatures
At lower temperatures, the color is a dull red. As the temperature increases, the red color brightens, and at even higher temperatures a brilliant white light is emitted.
How is wavelength related to temperature
The wavelength of the most intense radiation is related to temperature: As the temperature of the metal is raised, the maximum intensity shifts toward shorter wavelengths, that is, toward the ultraviolet
what is the ultraviolet catastrophe
Theories available at the time predicted that, as a solid is heated, the intensity should increase continuously with decreasing wavelength, instead of reaching a maximum and then declining as is actually ob-served. This perplexing situation became known as the ultraviolet ca-tastrophe because predictions failed in the ultraviolet region.
what did max planck offer?
Max Planck (1858–1947), offered an explanation for the ultraviolet catastrophe: The emitted electro-magnetic radiation originated in vibrating atoms (called oscillators) in the heated object. He proposed that each oscillator had a fundamen-tal frequency (ν) of oscillation and that these oscillators could only oscillate at either this frequency or whole-number multiples of it (nν).
Equation max planck proposed
Because of this, the emitted radiation could have only certain energies, given by the equation E=nhν
what is quantization
Quantization means that only certain energies are allowed
What is h
h in the equation is now called Planck’s constant
If an oscillator changes from a higher energy to a lower one, energy is emitted as electromagnetic radiation, where the difference in energy between the higher and lower energy states is
∆E=Ehigher n−Elower n=∆nhν
What did albert einstein incorporate into what explanation
A few years after Planck’s work, Albert Einstein (1879–1955) incorporated Planck’s ideas into an explanation of the photoelectric effect and in doing so changed the description of electromagnetic radiation.
What is ejected in the photoelectric effect
In the photoelectric effect, electrons are ejected when light strikes the surface of a metal (Figure6.4), but only if the frequency of the light is high enough.
How does light affect the electrons ejected?
If light with a lower frequency is used, no electrons are ejected, regardless of the light’s intensity (its brightness). If the frequency is at or above a minimum, critical frequency, increasing the light intensity causes more electrons to be ejected.
What are photons
That light has particle like properties. Einstein characterized these massless particles, now called photons, as packets of energy, and stated that the energy of each photon is proportional to the frequency of the radiation as defined by Planck’s equation.
wave like particle duality
wave–particle duality—that is, the idea that electromag-netic radiation has the properties of both a wave and a particle
What is line emission spectrum
The spectrum obtained in this manner is A line emission spectrum is caused when energy is added to an atom. This added energy causes the electrons in the atom to jump up energy levels. When this happens, the atom is in an excited state.
what does the balmer eq calculate
the Balmer equation was found that could be used to calculate the wavelength of the red, green, and blue lines in the visible emission spectrum of hydrogen
n stands for
energy level
l stands for
angular momentum
ml stands for
specific orbital
what must n be
always a positive interger
how to find l
n-1
l is equal to for the following orbitals:
s=0
p=1
d=2
f=3
how to find ml
-l…l
what is s shape
spherical
what is p shape
dumbbell. There are 3 p orbitals (x,y,z)
what is d shape
clover leaf shape. There are 5 d orbitals
what is ms
either +1/2 or -1/2
it indicates the spin
as energy size increases
the size of the orbital increases and the number of orbitals
As the number of orbitals increases
so does their complexity
number of energy level equals
number of sublevel
n=1
what sublevels
1s
n=2
what sublevels
2s 2p
n=3
what sublevels
3s 3p 3d
n=4
what sublevels
4s 4p 4d 4f
how many electrons can s hold
2
how many electrons can p hold
6
number of e that d can hold
10
number of e that f can hold
14
gray colored lobe is the
positive lobe
white colored lobe is
negative lobe
what info does l the angular momentum give us
the shape of the orbital
l= 0,1,2,3
s,p,d,f
energy increases in orbital order
s p d f
energy increases from left to right
He is part of
1s
where do transition metals have their valence electrons
in the d subshell, that means the d subshell is either half full or totally full
what are degenerate orbitals
energy is equal and the orbitals are at the same height
how to you do an orbital diagram
1 electron configuration
2 arrows in
the arrows are filled from lowest to highest aufbau
fill out degenerate orbitals one at a time hunds rule
number of transitions formula
n(n-1)/2
absorption
lower to higher
emission
higher to lower
of subshells =
n number
nodal surfaces =
type of orbital
spdf
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