CHEM 110 - MIDTERM #3 Flashcards
What is the principal quantum number?
Symbol: n
Values: positive values (1, 2, 3)
Property: Orbital energy (size)
The bigger the n value, the larger the orbital
What is the angular momentum?
Symbol: l
Values: 0, n-1
Property: orbital shape
Orbital shape of l=0
s-orbital (circle)
Orbital shape of l=1
p-orbital (dumbell)
Orbital shape of l=2
d-orbital (clover)
Orbital shape l=3
f-orbital (insane)
Collections of orbitals with the same n-value are _____
Shells (ie. 2s and 2p share the same 2nd shell because they both have n=2)
Collections of orbitals with the same n & l values are ___
subshells (ie. 2s and 2p are the same subshells)
Subshells of n=2
where l=1,0 -> 2p & 2s subshells respectively
What is the magnetic quantum number?
symbol: ml
values: + and - l (including 0)
property: orbital orientation in space (number of orbitals in a subshell with a particular l value)
# of ml values can be found with: 2l + 1
What is the spin quantum number?
symbol: ms
values: +1/2 or -1/2
property: direction of e- spin
if l=0, then how many ml values are there?
ml = 2l + 1 = ml = 1 value where ml=0
How many orbitals in l=0?
One orbital where s orbital is present and can only hold 2 electrons
How many orbitals in l=1?
3 orbitals where p orbital is present and can only hold 6 electrons
How many orbitals in l=2?
5 orbitals where d orbital is present and can only hold 10 electrons
How many orbitals in l=3?
7 orbitals where f orbital is present and can only hold 14 electrons
How many orbitals in l=4?
9 orbitals where g orbital is present and can only hold 18 electrons
Similarities and differences between 1s and 2s orbital?
Have different principal quantum numbers (n=1 vs. n=2); but have the same shell (at l=0). 2s is also larger than 1s in orbital size, but they share the same ml and ms values at l=0. 2s is further away from the the nucleus.
Difference between 2px and 2py?
Same n-value, same l value (same size and orbital shape); different orientations (ml=-1 at 2px and ml=0 at 2py).
What is an orbital?
electrons with the same values of n, l, and ml (n=3, l=2, ml=-2)
Energy of orbitals in a single electron atom rely on __
the principal quantum number (n)
Energy of orbitals in a multi-electron atom rely on __
n and l
What is the Aufbau principle?
States that the electrons fill in lowest energy orbitals (1s will fill up before 2s and 2p)
What is Hund’s Rule?
The most stable arrangement of electrons in subshells is the one with the greatest number of parallel spins (ie. 2p3) - you must put one electron in each orbital before adding the second electron in the orbital
Difference between paramagnetic and diamagnetic compounds?
Paramagnetic: unpaired electrons (ie. 2p2)
Diamagnetic: all electrons are paired (2p6)
Which EM region has the greatest energy?
Gamma rays
Which EM region has the least energy?
Radiowaves
Work equation?
W = -P x Change in V (in L)
When heat is absorbed it is ____?
Endothermic (+)
When heat is released onto the surroundings it is __?
Exothermic (-)
First law of thermodynamics equation?
Change in internal energy = heat exchange + work (U = q + w)
Negative work = _____
Expansion (-)
Positive work = ____
Compression (+)
Examples of state functions?
Energy, Enthalpy, Pressure
Is work a state function?
no lol
Temperature increases with the progression of the reaction = ____ reaction
Exothermic
Temperature decreases with progression of reaction = ___ reaction
Endothermic
Ideal gas law & thermodynamics =
U = H - RT(n) where:
U = change in internal energy
H= enthalpy
n = number of gas moles products - number of gas moles reactants
A combustion reaction is an ____ reaction
Exothermic
Standard enthalpy of O2?
0
Standard enthalpy of C, graphite?
0
Hess’ Law states that ____
enthalpy is a state function
Enthalpy of a reaction is equal to the _____ of compounds
molar ratios
(ie. 233 kJ of the reaction = 2 moles of H2 (g))
Visible light spectrum?
400-700 nm
@ 400 nm the color is?
blue/violet
@500 nm the color is?
green
@700 nm the color is?
red
@400 nm - the wavelength is ____, has a ____ frequency and ____ energy
shorter
higher
higher
@700 nm - the wavelength is ____, has a ____ frequency and ____ energy
longer
shorter
lower
Excited electron =
going from a higher to lower energy orbit (n=3 -> n =2)
Ground state electron =
n=1 (lowest level, closest to nucleus)
Emitted electron =
going from lower to higher energy orbit
momentum equation
p = mu (mass of electron x velocity)
Heisenberg Uncertainty Principle
States that position and momentum are uncertain of an electron
Pauli Exclusion Principle
No two electrons in the same atom can have the same quantum number (opposite spins of electrons and no more than two electrons in an orbital)
