Chemistry final

trend of atomic radius

decreases across a period and increases down a group

trend of ionization energy

decreases down a group (easier to remove electrons as you go down), increases across a period from left to right (harder to remove electrons as you move right).

inverse of atomic radius

How do the size of cations compare to the atoms from which they are formed?

Smaller; the more positive the ionic charge the smaller the radius

How do the size of anions compare to the atoms from which they are formed?

Larger; the more negative the charge the larger the radius

What are exceptions to the ionization energy trend?

Based on screening and penetration

ex) Al IE smaller than Mg;S lower than P

What is the trend for electron affinity?

increases across a period, decreases down a group

Diamagnetic

all electrons paired

weakly repelled by magnetic field

paramagnetic

Atom or substance containing unpaired electrons and is consequently attracted by a magnet.

Polarizability

measure of the ability of a charge to distort a molecule's charge distribution (electron cloud)

What is the periodic trend for polarizability

Increases with atomic radius

Polar covalent bond

electrons not shared equally and displaced toward more nonmetallic element

Electrostatic potential

work done in moving a uit of positive charge at a constant speed from one reigon of a molecule to the other

How can an electrostatic potential map be used?

gives info about distribution of electron charge

help determine polarity/nonpolarity

is this ionic or covalent

ionic

What is the trend for electronegativity?

It increases across a period and decreases down a group.

What kind of bond has a large EN difference

ionic

What kind of bond has small EN difference

covalent

What kind of bond has intermediate EN difference

polar covalent

What are exceptions to the octet rule?

Odd-electron species, incomplete octets, expanded octets

Concepts of Lewis Theory

valence electrons are important in bonding

each atom has octet

electrons shared between atoms in covalent

Starting point for VSEPR theory, valence bond theory, and orbital hybridization

Shortcomings of Lewis theory

does not explain delocalized charge or the need for resonance structures

VSEPR theory concepts

repulsion between pairs of electrons to predict of molecule

explains need for hybridization

VSEPR theory shortcoming

approximate, not exact bond angles

valence bond theory concepts

covalent bonds form from overlap of atomic orbitals

describes combination of half-filled atomic orbitals to create molecular orbitals

Valence bond theory shortcomings

ionized picture of bonding

does not describe delocalization

predicts 90 degree bond angles from overlap of p atomic orbitals

needs to be combined with hybridization

Hybridization main concepts

atomic orbitals can be combined into hybrid orbitals to reconcile observed molecular geometry with valence bond theory

useful for predicting molecular geometry around carbon

hybridization shortcomings

not exact solutions to schrodinger equation

debate about d orbitals

Molecular orbital theory concepts

atomic orbitals combine in constructive and destructive ways to create new molecular orbitals

debate about d orbital

determine bond order and predict magnetic properties

delocalized charges well

What is the geometries, bond angle, and hybridization BeCl2

linear, 180, sp

What is the geometries, bond angle, and hybridization of BF3

trigonal planar, 120, sp2

What is the geometries, bond angle, and hybridization of SO2

bent/trigonal planar,

What is the geometries, bond angle, and hybridization of CH4

tetrahedral, 109.5, sp3

What is the geometries, bond angle, and hybridization of NH3

trigonal pyramidal/tetrahedral,

What is the geometries, bond angle, and hybridization of OH2

bent/tetrahedral,

What is the geometries, bond angle, and hybridization of PCl5

trigonal bipyramidal, 90 and 120, sp3d

What is the geometries, bond angle, and hybridization of SF4

seesaw, 90 adn 120, sp3d

What is the geometries, bond angle, and hybridization of ClF3

T-shaped, 90, sp3d

What is the geometries, bond angle, and hybridization of XeF2

linear, 180, sp3d

What is the geometries, bond angle, and hybridization of SF6

octahedral, 90, sp3d2

What is the geometries, bond angle, and hybridization of BrF5

square pyramidal, 90, sp3d2

What is the geometries, bond angle, and hybridization of XeF4

square planar, 90, sp3d2

order of repulsive forces

lone-pair lone-pair> lone pair-bond pair > bond pair-bond pair

London dispersion forces

the intermolecular attraction resulting from the uneven distribution of electrons and the creation of temporary dipoles

Relationship between London Dispersion forces and molar mass

HIgher molar mass higher LDF

Relationship between temperature and vapor pressure

Higher temp = higher vapor pressure

relationship between IMF and enthalpy ofvaporization

higher IMG = Higher enthalpy of vaporization

Relationship between IMF and vapor pressure

Higher IMG = Lower vapor pressure

Is vapor pressure intrinsic or extensic?

intrinsic

Clausius-Clapeyron equation

mathematical relationship between the temperature, vapor pressure, and enthalpy of vaporization for a substance

Deposition

gas to solid

Sublimation

solid to gas

Condensation

Gas to liquid

Evaporation

Liquid to gas

Melting

solid to liquid

Freezing

liquid to solid

lattice energy

the energy released when one mole of an ionic crystalline compound is formed from gaseous ions

standard enthalpy of formation

enthalpy change if 1 mole of compound in standard state were formed directly from its elements

Relationship between molecule branching and London Dispersion force strenght

Increase in branching (aka surface area,) increase in LDF

What is a critical point?

the temperature and pressure at which liquids and gases become indistinguishable

What is a triple point

the temperature and pressure at which all three phases of matter coexist in an equilibrium

solid water is ______ dense than liquid water

less

Why is solid water less dense than liquid water?

negative phase change slope between solid and liquid

Equation for entropy Isothermal (only pressure change)

Equation for entropy Isobaric (only change in Temperature)

3rd law of thermodynamics

entropy at 0 K = 0

Relationship between entropy and temperature

increased temp = increased entropy

Molecule complexity and entropy

molecule complexity higher = higher entropy

2nd law of thermodynamics

Every energy transfer or transformation increases the entropy of the universe.

A reaction where bonds are broken is ___

endothermic because more energy goes into system

A reaction where more bonds are formed is __

Exothermic because forming bonds releases energy

Gibbs free energy equation

How do we determine spontaneity based on properties of the system alone?

Gibbs Free Energy

Spontaneity and entropy of the universe

Gibbs Free Energy and Spontaneity

Spontaneity with negative enthalpy and positive entropy

Spontaneous all temperatures

Spontaneity with negative enthalpy and negative entropy

Spontaneous at low temperatures

Spontaneity with positive enthalpy and positive entropy

spontaneous high temperatures

Spontaneity with positive enthalpy and negative entropy

nonSpontaneous at all temperatures

Is Gibbs free energy a state function? Can hess' law apply

yes; Hess' law can be applied

reactant quotient

Describe extent of reaction

Gibbs energy of reaction and reaction quotient

Relationship between Q and reaciton conditions

Gibbs standard free energy and K

Activity of pure solids/liquids

1

Activity for gases

Numerical pressure in bar (very close to atm)

Activity of solutes in aqueous solution

Molarity

What does a large K value mean

products are more thermodynamically stable than reactions in standard states

What does a small K value mean

products less thermodynamically stable than reactants

relationship between K and Temperature

Chemical Potential

A substance's ability to change gibbs energy of the system

How is K affected when reaction multiplied by coefficient x

K^x

How is K affected when reaction divided by coefficient x

K^(1/x)

How do you combine K values for two reactants that can be added together?

mutliply K values

How is K affected when reaction reversed

1/K

Are ionic compounds soluble in polar solvents?

Most are

What are molecular solids?

covalently bonded molecule

What are nonpolar molecular solids soluble in?

Soluble in some nonpolar solvents

What are polar molecular solids soluble in?

Soluble in some nonpolar and polar solvents

What are molecular solids with hydrogen bonding soluble in?

Soluble in polar or hydrogen bonded solvents (Water)

How does attractive force between oppositely charged ions change with increased charge?

Attractive force increases