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88 Cards in this Set

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What was Dalton's atomic theory that can into question 50 years later?
that the atom is indivisible.
Joseph John Thomson
He realized that the accepted model of an indivisible atom did not take electrons and protons into account. So he referred it to as the "plum pudding atom" where the negatively charged electrons (raisons) are stuck into a lump of positively charged protons (the dough.)
what was the error in the plum pudding atom and who had suggested it?
Joseph John Thomson. He didn't mention the number of protons, their arrangement in the atom or th ease with which atoms are stripped to electrons to form ions.
Ernest Rutherford
Based on his discovery of the nucleus, he proposed the nuclear atom in which electrons surround a dense nucleus. He thought the rest of the atom as empty space.
What was the "error" in Rutherford's model?
People asked, what prevents the electrons from falling into the nucleus?
Niels Bohr
Niels Bohr, a young Danish physicist and a student of Rutherford's came up with a new model. He proposed that the electrons are arranged in circular paths, or orbits, the way the plants around in the sun.
what is an energy level?
The energy level of an electron is the region around the nucleus where ti is likely to be moving.
Quantum
A quantum of energy is the amount of energy required to move an electron from its present energy level to the next higher one.
Austrian physicist Erwin Schrodinger
he used new quantum theory: The quantum mechanical model deriving from the Schrodinger equation.
What are principal quantum numbers?
n, which is the energy levels fo electrons. They are assigned certain values: n= 1,2,3,4,5,6 etc.
Within each principal energy level there lies
several electron cloud shapes.
When the quantum mechanical model divides the energy level into energy sublevels,
each sublevel corresponds to a different cloud shape (atomic orbital) which is a region in space where there is a high probability of finding an electron.
s-shape
spherical
p-shape
dumbell
d-shaped
star shaped
electron configurations
the ways in which electrons are arranged around the nuclei of atoms
aufbau principle
Electrons enter orbitals of lowest energy.
The Pauli Exclusion principle
An atomic orbital may describe at most two electrons
Hund's rule
When electrons occupy orbitals of equal energy, one electron enters each orbital until all the orbital contains one electron with spins parallel.
Electromagnetic radiation
includes radio waves, microwaves, visible light, infared and ultraviolet light, X-rays, and gamma rays.
The amplitude of a wave is
the height of the wave from the origin to the crest.
the Wavelength (the thing that looks like a "person" in chinese character)
is called lambda, and it represents wavelength (distance between the crests)
Frequency
is v, called nu, which represents the frequency, the number of wave cycles to pass a given pint per unit of time.
The frequency and wavelength of light are ___ related
inversely.
Hertz
In the SI, units of cycles per second are called hertz. Hz.
When sunlight is passed through a prism the light is separated into a ______ of colors.
spectrum
Passing the light emitted by an element through a prism gives the ___ of the element
atomic emission spectrum.
Max Planck
Planck was trying to quantitatively describe why a bod like a chunk of iron changes color when heated.
h
planck's constant: 6.6262 x 10^-34 J/s
How do you find energy?
Energy of a quantum equals h x v.

E(energy)=h(Planck's constant) x v(nu)
Albert Einstein
Proposed that light could be described as quanta of energy that behave as particles

light quanta=photons
What is the photoelectric effect?
In the photoelectric effect, electrons called photoelectrons are ejected by metals when light shines on them.
ground state
when it is at the lowest energy level n=1
Louis de Broglie
A french graduate student, asked an important question. Since light behaves as waves and particles, can particles of matter behave as waves?

lanbda= plack's constant divided by mass and v (v being the velocity)

De Broglie's equation predicts that all matter exhibits wavelike motions.
The Heisenberg uncertainty principle (Werner Heisenberg, a physicist)
The uncertainty principle states that it is impossible to know exactly both the velocity and the position of the particle at the same time.
list the visible wavelength in order of increasing wavelength
(The longer the wavelength, the shorter the frequency)
(highest frequency, lowest wavelength) Violet, blue, green, yellow, orange, red (lowest frequency, highest wavelength)
list the waves by increasing frequency
radio waves, microwaves, infared, visible light, ultraviolet, x-rays, gamma rays
list the waves by increasing wave length
gamma rays, x-rays, ultraviolet, visible light, infared, microwaves, and radio waves.
Isaac Newton developed thought of light as consisting of particles, what was so important about that?
scientists had light as wave length engraved in the minds
Wave cycle
each wave cycle begins at the origin, then returns to the origin
frequency
nu. the # of wave cycles to pass through a given point per unit of time.
amplitude
the height of the wave from the origin to the crest
wavelength
is the distance between the crests.
what was so important about planck's proposal?
he proposed absorption or emission of quanta of energy. Chemists believed that there was no limitation to the smallness of permissible energy changes in a system. For example, water, seems to have a fixed boiling point but it's just that it's getting hotter by infinitesimally small steps.
E= h x v(nu) (Frequency)
Only when you reach the threshold frequency
do photons move the electrons.
Why is the photoelectric effect unable to be explained by classical physics?
because in physics, there is no quantum concept. Classical physics correctly view light as a form of energy. But ti assumed that under weak light, any electron in a metal could "collect" enough energy to be ejected.
In photoelectric effect, if the intensity of the light is increased, whilst frequency stays the same...
more electrons bounce off, although they bounce off at same rate.
In photoelectric effect if the wavelength is shorter, (frequency gets higher)...
the electron that bounces off, bounces off at a higher speed.
What's the difference between a quantum and a photon?
quantum is the amount of energy required to move an electron to one higher energy level whilst a photon are light quantas
what the difference of an excited and a ground state?
a quantum of energy whether emitted or absorbed : h x v
Lyman Series
ultraviolet light
Balmer Series
Visible light
Paschen series
Infared Series
James Clerk Maxwell
proposed that visible light is composed of electromagnetic waves

waves: A vibrating disturbance by which energy is transmitted
Speed of light, C, is
C= 3 x 10^8 m/s
electromagnetic radiation is
energy propagated at the speed of light. C=lanmda x nu
C=wavelength x frequency
Hertz=Hz
frequency= hertz= 1/s= s^-1
radio waves
nu: 10^8 lambda: 10^0=1
James Clerk Maxwell
proposed that visible light is composed of electromagnetic waves

waves: A vibrating disturbance by which energy is transmitted
Speed of light, C, is
C= 3 x 10^8 m/s
electromagnetic radiation is
energy propagated at the speed of light. C=lanmda x nu
C=wavelength x frequency
Hertz=Hz
frequency= hertz= 1/s= s^-1
radio waves
nu: 10^8 lambda: 10^0=1
microwaves. Remember, wavelengths are measured in meters. (m)
nu: 10^11 Lambda: 10^-3
infared radiation
nu: 10^13 Lambda: 10^-3
visible light
nu: 10^15 Lambda: 10^-7
ultraviolet radiation
nu: 10^17 Lambda: 10^-9
x-rays
nu: 10^19 Lambda: 10^-11
gamma rays
nu: 10^21 Lambda: 10^-13
whilst high frequency is short wave length
low frequency is long wave length
Max Planck: Energy is always emitted in multiples of
hv (n) being an integer

Electromagnetic radiation released by an object can have only discrete values, unlike classical assumption of continuous range of values
Albert Einstein talked of photons (electrons released by metals)
hv=binding E + kinetic E

Kinetic E= (1/2mv^2)= hv-hv0

KE=HV-BE
photon
hv. Photoelectric effect, minimum threshold frequency for ejection of electrons

(does not depend on intensity, but rather, frequency)
wave/particle duality
light behaves as either as waves or particles
Neils Bohr
explained the emission spectrum of a hydrogen atom on basis on quantization of electron energy

emission spectrum: Light is separated into different components when passed through a prism.
A group of hydrogen lines in the visible range is called the
Balmer's series
Rydberg constant
Johannes Rhdberg

1.0968 x 10^7m^-1

1/lambda=R (1/2^2(4)-1/n^2)
When is energy emitted?
when it goes from a higher (excited state) to a lower state. The lowest is called the (ground state)

Bohr thought of orbitals. But electrons can only fit into one orbital, or the other, no in-betweens
to calculate difference of energy from one state to the other
Energy= -2.178 x 10^-18 (1/n^2 - 1/n^2)


the first n being the initial (or final) and the second being the final (or initial) Just make sure it ends up as a positive #
Louis de Broglie
wave/particle duality.

he showed that electrons had wave properties. He asked that if light can behave as particles and waves, can't any other object in nature?

Smaller the mass, greater the wave length:

lambda= planck's constant/mass x velocity

lmabda= h/mv

The circumference of a circular orbit has to correspond to a whole number of orbits.
Einstein's theory of relativity
E=mc^2

Energy= mass x (speed of light)^2
werner heisenberg
uncertainty principle

(change in x)(change in p)=planck's constant/4 x pie

(change in= CI)
(CI:X)(CI:p)=h/4(pie)

X is position: P is momentum
Erwin Schrodinger
wave (quantum) mechanics : Emphasis on wave properties of electron
principal quantum number:
n (related to size and energy) always in integral number: 1,2,3,etc
angular momentum number:
l (Related to shape of the orbital) Integral values: 0,1,2,(n-1)

when l=0 it's a s orbital
when l=1 it's a p orbital
when l=2 it's a d orbital
when l=3 it's an f orbital
magnetic quantum number:
Ml (related to orientation of orbital in space)

the integral difference of l and -l
what is the boundary surface?
where you'd find 90% of total electron probability. chemists approximate the orbital to the boundary surface.
Spin Quantum Number Ms
It has no relation on size, energy, orbital, anything, but it is very important in determining electron configuration. Ms may have any of these two values: +1/2 or -1/2