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34 Cards in this Set

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quantum mechanics
n = shell
l = subshell; 0->n-1

ml = orbital; -l->l; 2l+1 orbitals in subshell

ms = spin; -1/2->1/2
periodic trends
atomic radius: increases going down and decreases left to right

electronegativity: how strong atom holds unto electrons in chemical bond; increases left to right and decreases going down

ionization energy: energy required to completely remove electron from gaseous atom or ion; trend follows EN

electron affinity: energy release when gaseous atom or ion gains an electron
group B elements
-transition elements

-partly filled or filled d subshells

-form coordination complexes that are highly colored

-inner transition elements are lathanide and actinide series that have partly filled or filled subshells
types of bonds
-ionic bonds occur between metals and nonmetals with large EN differences

-covalent bonds occur between nonmetals and involves the sharing of electrons

-polar covalent bonds occur between atoms with different EN and produces a molecule with partial ionic character

-nonpolar covalent occurs between atoms with the same EN and is found in diatomic molecules
intermolecular forces
ion-dipole: between polar and ionic molecules; ex: NaCl dissolved in water

hydrogen bonds: occurs between atoms w/ H bonded to a highly EN atom and found to occur in water, alcohols, amines, and carboxylic acids

dipole-dipole: between polar molecules

dispersion forces: found in nonpolar molecules and involves transient dipoles that arise from random fluctuations of electron density
what elements violate the octet rule?
H, Be, B (incomplete octets) and elements from period 3 and down (more than 8)
formal charge
= # valence electrons - 1/2bonding + nonbonding

helps determine alternate lewis structures and the one with the smallest formal charge is preferred
lewis structures
-determine # valence electrons in molecule
-put least EN atom in the center (usually C)
-H and halogens usually on the outside
-single bonds first
-complete octets on outer elements
-any extra electrons put unto center atom
-if center atom had incomplete octet, use multiple bonds until it is complete
pressure
force per unit area that gas molecule exert on the walls of the container

1 atm = 760 mm Hg = 760 torr
standard conditions
-298K and 1 atm
STP
-273K and 1 atm

-gases often discussed in terms of STP
Ideal Gas Law Assumptions
-gas particles take up no volume

-no intermolecular attractions between gas particles

-random motion and they collide with eachother and walls of container elastically

-KE proportional to T and is the same for all gases at a given T
mole fraction and partial pressure
-mole fraction is equal to mol of gas X / total mol. of all gases present

-partial pressure is equal to (total P)(mole fraction)
rate law
in the rxn aA + bB -> cC + dD

rate = [A]^x [B]^y

where rxn order determined experimentally

overall rxn order is x + y
factors affecting rxn rate
-reactant concentration

-temperature

-catalyst

-solvent
equilibrium
dynamic state in which forward and reverse reactions are equal
equilibrium expression
-products over reactants

-pure solids and liquids not included in equilibrium expression

-if Keq more than 1 then there are more products around
Le Chatelier's Principle
-if stress applied to sytem, sytem will respond in a way to relieve stress

-increase concentration of substance -> use it up and dec. its concentration

-increase pressure -> decrease number of moles of substance

-when temperature increased in endothermic rxn, rxn will shift to right; temp. dec. causes a shift to left to produce heat

-when temperature is increased in an exothermic rxn, rxn will shift to left; if temp. dec. , rxn will shift to right to produce more heat to inc. temp.
solubility product constant
-equilibrium of dissolved and solid solute

-describes concentrations at saturation level in which adding more solute causes solute to settle at the bottom

-remember, pure solids and liquids don't appear in equilibrium expression

-higher the solubility product constant, harder it is to reach saturation

-generally inc. w/ inc. temp.
molar solubility
-molar solubility is max moles of a substance that will dissolve in 1L of solution
first law of thermodynamics
-energy is conserved

-energy of a syste, can change by heat change or doing work

-E = Q - W

-E = Q + W
entropy
-measure of disorder

-energy/temperature

-increases with temperature
second law of thermodynamics
-all spontaneous processes in an isolated system lead to an increase in entropy
enthalpy
-heat change of a rxn
standard heat of formation
-enthalpy change that occurs when a compound is formed froms its elements in their standard states
Avogadro's number
-6.022 x 10^23 particles

-1 gram = 6.022 x 10^23 amu
quantum
-discrete bundles of energy emitted as electromagnetic radiation from matter

-energy value is E = hf
what is the centripetal force that acts on an electron as it revolves around the nucleus
-the electrical force between the positively charged proton and negatively charged electron
what do Planck's energy and the angular momentum of an electron have in common?
-they're both quatitized

-Planck's energy depends on frequency of radiation

-angular momentum depends on quantum # b/c everything else on angular momentum = nh /2 (3.14) is a constant
energy of an electron
-E = -RH/n^2

-as quantum # increases, energy increases

-energy changes as quantum # changes

-zero energy when electron and proton completely seperated
(no attractive force)

-electron in any of its quantitized states has negative energy
the smaller the radius the lower/higher the energy state of the electron?
lower
what happens when electrons return to groud state after being excited?
-they emit energy in the form of photons

-electromagnetic energy of these photons are E = hc/(wavelength)

-different electrons in an atom will be excited to different energy levels and they will thus emit different photons characteristic of its transition

-line spectrum produced

-each element can have its electrons excited to different distinct energy levels, thus each one possesses a unique atomic emission spectrum

-transition from one quantum # to another is equal to the energy of Planck's emitted photon (depends on frequency)

-balmer and lyman series for hydrogen emission lines

-each element also has a characteristic absorption spectrum b/c electrons absorb energy when they're excited

-absorption corresponds to emission (equals energy difference between levels)
where are electrons located?
-orbitals

-Bohr's assumption that electron follow a fixed orbital dastance is no longer valid
energy state of an electron
-position and energy of an electron described by its quantum numbers