Exam 2 Flashcards
Frequency
V
Wavelength
λ
Frequency measured in
hertz
Wavelength measured in
nm
Speed of light (on formula sheet)
C
3.00 * 108 m/s (
Energy and Frequency
Directly proportional
Energy and Wavelength
Inversely proportional
Wavelength and Frequency
Inversely Proportional
Energy of a photon equations (2 equations)
E= h * v (on formula sheet)
E= h*c/λ
E=J/Photon
What is h?
Planck’s constant
6.26*10-34J/s
(on formula sheet)
convert m to nm
convert m to um
1m= 1*109nm
1m=1*106um
ROYGBIV
Red low energy, longest wavelength. (infrared next to red)
Violet is highest energy, shortest wavelength. (UV next to violet)
ROYGBIV
Energy ——>
Frequency ——>
<————wavelength
Remember: Wavelength is inversely proportional!
Avagadros for light problems!
1 mol of photons/6.022*10^23 photons
Take something like #KJ/mol. Convert KJ to J then multiply by 1mol/6.022*1023photons so you get J/photon that can be used in E equations. E=hc/λ
Or if you have number of J/photon and want it in moles, multiply by 6.022*1023photons/1mole.
E=hc/λ
λ should be what unit?
METERS
q=mc∆T
c=4.184 J/gC heat capacity of water
m is mass in grams
Electron moving to a different energy level
only if it absorbs or emits a photon that has the same energy as the difference between the two energy levels
ground state
lowest energy oribtal n=1 for hydrogen
Excited State
When the electron is at a higher energy orbital n=2+ for hydrogen
Ionize
When an electron is ejected from an atom. Nfinal=infinity.
Losing an electron.
Exothermic and endothermic electrons
Electrons go from a high level (7) to a low level (2). ∆H= neg. Emission!
Endothermic go from low (2) to a high level (7). Absorption!
Lyman series
UV 90-100nm
ends at n=1
Balmer Series
400 to 700
Ends at n=2
Visible Light
IR series
IR 1000 nms
ends at n=3
all the series are exothermic BTW. High to low level.
Rydberg Equation Wavelength of electron transition in a Hydrogen atom
(all given on formula sheet)
1/λ =R(1/n12-n22)
n2>n1!!
R=1.097*107
Rydberg for energy transition (other one was to calculate wavelength)
RHC*Z2(1/nfinal2-1/ninitial2)
z=# of protons element has – so 1 for hydrogen.
RHC= -2.18*10-18
wavelength, mass, and speed– de broglie
λ =h/mu
mass in kg, u is speed in m/s and h is planck’s.
emissions at n=1
anything going or coming to n=1 has highest E. Passes through lots of levels. Or could use the rhc equation.
n
level (look at periodic table row).
Indicates relative distance
higher th enumber, greater the distance of the orbital from the nuclues, larger the shell, higher energy.
l
subshell
max value: of n-1. Max number of possible l values=n
Indicates shape
s, p, and d l values and shape
s =0; sphere
p=1; dumbbell
d=2; double dumbbell
f=3; flower
ml
-1 to +1 range.
Orientation.
labeling the slotsof the orbitals e.g. if p: -1, 0, 1 for the 3 slots.p l value is 1.
Pauli Exclusion principle
max number of e per orbital is 2
Hund’s rule
Fill with one e in each orbital, then go back and fill in the rest.
ms
-1/2 or +1/2
if up arrow, positive.
represents magnetic field
testing quantum validity
n>l> or equal to |ml|.
pauli exclusion principle
no 2 e in the same atom can have the same 4 quantum numbers.
2 e in an orbital must have opposing signs
aufbau principle
filling orbitals with the lowest energy
Z or nuclear charge
electrong is attracted to teh positive charge of the nucleus
Electron Shielding
If there are several electrons in the same orbital, they repel each other and shield one another from the attractive force of the nucleus (prevents feeling of full nuclear charge-Z). Experience an effective nucleuar charge (Zeff) due to shiledings. Effective shielding done by inner electrons loweres the effect of Zeff on outer electrons.
There is more shielding in the p orbital- easier to remove a p orbital electron.