Theory and Problem Solving Flashcards
(60 cards)
1
Q
Expanded octets are only for
A
elements in period 3 and beyond because they have empty d orbitals
2
Q
Bond energies
- which one is positive and negative, and what is the equation
A
delta H of bonds broken-formed
formation: - (hence why the equation is a minus)
breaking: +
3
Q
Electron groups for geometry
A
- single and double bonds are counted as 1 group
- lone pairs count as 1 group
4
Q
Forming H bonds
A
- When H atoms that are far apart approach each other, PE=0
5
Q
electron domain/charge cloud
refers to what
A
electron geometry
6
Q
Determining the number of degenerate orbitals needed
A
Use trial and error:
For example: Cl: ? degenerate orbitals for 7 electrons with 5 unpaired
= you would need 6
7
Q
For elements n=3 and above (hybridization)
A
switch to d
- sp^3 is fine
- sp^4 is not it should be sp^3d
8
Q
Bond order is
A
number of bonds (double and single aren’t tx equal) /bond position (surrounding atoms)
9
Q
p-p make up
A
pi bond
10
Q
LOW IMF refers to
A
- low viscosity
- low surface tension
- high vapour pressure
- low BP
11
Q
HIGH IMF refers to
A
- high viscosity
- high surface tension
- low vapour pressure
- high BP
12
Q
Difference in BP between Octane and Isooctane
A
iso: 5 C-H with 3 methyl
oct: straight C-H (stronger IMF)
13
Q
Sublimination
A
solid to gas
= ENDOTHERMIC
14
Q
deposition
A
gas to solid
= EXOTHERMIC
15
Q
melting
A
- also called fusion
solid to liquid
= ENDOTHERMIC
16
Q
freezing
A
- liquid to solid
= EXOTHERMIC
17
Q
vaporization
A
- also called evaporation
- liquid to gas
= ENDOTHERMIC
18
Q
condensation
A
- gas to liquid
= EXOTHERMIC
19
Q
TRIPLE POINT
A
- all 3 phases touch
- all 3 equilibriums meet
= T + P for all reactions is good to occur simultaneously
so you get gas, solid, liquid particles
20
Q
CRITICAL POINT
A
point where liquid and gas are indistinguishable
- merge as a single phase
21
Q
Determining states on curve
A
the one flowing along x axis= GAS
the one by y axis= SOLID
the one between = LIQUID
22
Q
solving curve questions
A
- break temperature change down into steps
23
Q
free radicals
A
- exception to octet, O will get the electrons if there’s an odd number
- identify: any O atom with unpaired electrons
24
Q
Energy is directly proportional to
A
q1q2/r
= use this relationship to determine the energy released between two ions
25
Bond energy, order, and length relationship
- Higher bond order means stronger bonds (higher bond energy) and shorter bond lengths
-while lower bond order means weaker bonds (lower bond energy) and longer bond lengths.
*a higher bond order indicates more shared electrons between atoms, increasing the attractive force and pulling the nuclei closer together, shortening the bond.*
26
For curve q: Use R
with only J/mol/K
none of pv=nRT
27
room temperature
25 degrees celsius
28
Pressure at room temperature
1.01 bar
29
MO: pi orbitals only start
at p orbitals
30
Which elements use which MO diagram
O-Ne: sigma, pi, pi, sigma
Li-N: pi, sigma, pi, sigma
(for 2p)
31
electrolytes
substance that conducts electricity in solution
STRONG: dissociating completely (e.g., strong acids, bases, salts)
WEAK: partially dissociating (e.g., weak acids and bases).
32
percent yield
actual/theoretical (100%)
33
Electrical conductivity
High electrical conductivity comes from ionic compounds that fully dissociate in water, such as salts, strong acids, and strong bases.
= ability to transfer electrons
34
q, H, U chart
Exothermic: Enthalpy (ΔH), heat (q), and internal energy (ΔU) are negative.
Endothermic: Enthalpy (ΔH), heat (q), and internal energy (ΔU) are positive.
35
HUNDS, AUFBAU, AND PAULI EXCEPTIONS
Hund's Rule: Electrons fill degenerate orbitals singly before pairing.
Aufbau Principle: Electrons fill orbitals from lowest to highest energy.
Exception: Transition metals and lanthanides often have electron configurations that differ (e.g., Cr, Cu + elements after period 3)
typically involve transition metals in periods 4-6 (like Cr, Cu, Mo, Ag) and involve d-orbital stability
Pauli Exclusion Principle: No two electrons in an atom can have the same set of quantum numbers.
Exception: None.
36
shielding
reduction of the effective nuclear charge on an electron due to repulsion from other electrons.
37
lattice energy
energy required to separate one mole of an ionic compound into its gaseous ions.
- charge based too ions with greater charges will have higher lattice energies
38
covalent radius
covalent radius is the distance between two bonded atoms, while the atomic radius is the size of an isolated atom
39
work function of an element
work function is the minimum energy needed to remove an electron from the surface of an element
ϕ=hνthreshold
40
determining oxidation states of elements
Assign known oxidation states (e.g., O = -2, H = +1).
Sum of oxidation states in a neutral compound = 0, in a polyatomic ion = charge of ion.
Solve for unknown oxidation states based on these rules.
41
kinetic molecular theory
gas particles are in constant, random motion, colliding with each other and the container walls. These collisions are elastic, and the average kinetic energy is proportional to the temperature.
42
photoelectric effect
phenomenon where electrons are ejected from a material's surface when it absorbs light of sufficient energy.
43
effective nuclear charge
Zeff= Z - S
Z = atomic number
S (based on electron config): 0.85(1s electrons) + 0.35 (2s+p)
44
pressure-volume work theorem
-PV
45
STP
0° Celsius (273.15 K)
Pressure: 100 kPa (1 bar)
Molar volume: 22.4 L
46
trends
ATOMIC RADIUS: increases down and left
IE: increases up and right
ELECTRONEGATIVITY: increases up and right
ELECTRON AFFINITY: increases up and right
METALLIC CHARACTER: increases down and left
ATOMIC RADIUS
METALLIC CHARACTER
ELECTRON AFFINITY
ELECTRONEGATIVITY
IONIZATION ENERGY
47
nodes
- region where there are no electrons
Radial nodes: Spherical regions where the probability of finding an electron is zero.
Equation: n-l-1
Angular nodes: Planar or conical regions where the probability is zero.
Equation: l
TOTAL: n-1
48
What will be the case if an electron is emitted?
hv must be greater than work function
49
doing work on a system
endothermic
relates to W
50
losing or gaining heat
losing: - q
gaining: +q
51
E comb
delta Hr
52
What is Erxn
What is Hrxn
- a measure of change of energy (same as delta U)
- a measure of reaction
53
Delta U is
H-W
54
why are atoms roughly spherical
because when the different shaped orbitals are overlapped, they take on a spherical shape
55
determining transitions of n values
- lower the number the greater the energy level
56
exothermic reactions
- weak bonds break and strong bonds form
57
VSEPER
theory predicts molecular geometry by minimizing repulsion between electron pairs (bonding and nonbonding) around a central atom to achieve the most stable arrangement.
58
born haber order
Sublimation of metal (solid to gas) → up
Bond dissociation of nonmetal (if diatomic, break into atoms) → up
Ionization energy of metal (remove electron) → up
Electron affinity of nonmetal (add electron) → down
Lattice energy (formation of ionic solid) → down
59
MO
describes the electronic structure of molecules by combining atomic orbitals to form molecular orbitals, which are spread over the entire molecule and can be bonding, antibonding, or nonbonding, explaining properties like bond order, magnetism, and stability.
60
normal boiling point
boiling point
a) the temp when vapour pressure of liquid is around 1 bar
b) temp when vapour pressure of liquid = external pressure
