Chem 1127 – Final Exam Flashcard

Wavelength
the distance between 2 consecutive crests or troughs often measured in meters or nanometers
crest
rise above midline
trough
sink below midline
frequency
the number of wave cycles that pass a given point in unit time often measured in hertz
wave cycles
successive crests or troughs
?
wavelength
v
frequency
c
speed of light
speed of light
2.998E8 m/s
light visible to the eye
400-700nm
photons
stream of particles that generates light
unit of energy
joule (J)
E
hv
energy
inversely related to wavelength
h
planck’s constant
1nm
10^-9m
h
6.626E-34Js
1kj
10^3J
En
enery of the electron
-Rh
2.180E-18J
n^2
the principle quantum number
the point at which the proton and electron are completely separated
zero
ground state
lowest energy state for which n=1
excited state
when an electron absorbs enough energy it moves to this
hv
enery of the photon
v=RH/h [1/(nlo)^2 – 1/(nhi)^2]
used to find the frequency or wavelength of any of the lines in the H spectrum
kinetic energy of an electron
inversely related to the volume of the region to which it is confined
orbital
probability is independent of direction
quantum numbers
n, l, m(under)l
?
wave function
from ?
we can deduce the relative energy of that orbital, its shape, and orientation in space
principle energy levels
primary importance in determining the energy of an electron
energy of H atom
depends only on n
as n increases
the energy of the electron increases and on average is found farther out from nucleus
sublevels of second quantum number
s, p, d, f
second quantum number
l
l determines
general shape of electron cloud associated with an electron
larger values of l =
more complex shapes
if n=1
l has to be 0
in the nth principal level
there are n levels
for atoms containing more than one electron
the energy is dependent on l and n
orbitals
differ from one another in the value assigned to the third quantum number, m(under)l
m(under)l
determines the direction in space of the electron cloud surrounding the nucleus
all orbitals in a given d or f sublevel
have the same energy
electron spin
associated with the fourth quantum number, m(under)s
m(under)s
not related to n, l, or m(under)l
parallel spins
electrons that have the same value of m(under)s (i.e. both +1/2 or both -1/2)
opposed spins
electrons that have different m(under)s values (i.e. one +1/2 and one -1/2)
Pauli Exclusion Principle
requires that no two electrons in an atom can have the same set of four quantum numbers
capacity for electrons in an s sublevel
2e-
capacity for electrons in a p sublevel
6e-

capacity for electrons in a f sublevel

14e-
total capacity for electrons in the fourth principal level
32e-
s sublevel
spherical
p sublevel
two lobes along an axis
electron configuration
shows the number of electrons indicated by a superscript in each sublevel
electrons enter the available sublevels
in order of increasing sublevel energy
orbital diagrams
shows how electrons are distributed among orbitals
Hund’s Rule
when several orbitals of equal energy are available, as in a given sublevel, electrons enter singly with parallel spins
paramagnetic
if there are unpaired electrons present, the solid will be attracted into the field
diamagnetic
if the atoms in the solid contain only paired electrons, it is slightly repelled by the field
when a monatomic ion is formed from an atom
electrons are added to or removed from sublevels in the highest principal energy level
isoelectronic
having the same electron configuration
all transition metals form cations by
loss of outer s electrons
atomic radii decreases
left to right
atomic radii increases
up to down
ionization energy
a measure of how difficult it is to remove an electron from a gaseous atom
to bring about ionization, energy must be
absorbed
ionization energies are always
positive quantities
ionization energy increases
across the periodic table from left to right
ionization energy decreases
moving down the periodic table
electronegativity
measures the ability of an atom to attract to itself the electron pair forming a covalent bond
the greater the electronegativity of an atom
the greater its attraction for electrons
electronegativity increases
moving from left to right across the periodic table
electronegativity decreases
moving down a group in the periodic table
valence electrons
outermost principal energy level
core electrongs
fill the principal level n=1
covalent bond
a pair of electrons shared between two atoms
lone pair
an unshared pair of electrons, owned entirely by one atom
single bond
a single electron pair shared between two bonded atoms
octet rule
nonmetals, except for H, achieve a noble-gas structure by sharing in an octet of electrons
resonance hybrid
the actual structure as an intermediate between the two resonant forms
formal charge
the difference between the number of VE in the free atom and the number assigned to that atom in the Lewis structure
free radicals
molecules containing an odd number of VE
molecular geometry can be predicted on the basis of
electron-pair repulsion
VSEPR model
the VE pairs surrounding an atom repel one another so orbitals containing those electron pairs are oriented to be as far apart as possible
trigonal planar
120
tetrahedron
109.5 AX4
trigonal bipyramid
AX5
octahedral
AX6
polar
as a result of an unsymmetrical distribution of electrons, the bond or molecule contains a positive and a negative pole
dipole
contains a positive and a negative pole
nonpolar
a symmetrical distribution of electrons leads to a bond or molecule with no positive or negative poles
nonpolar bonds
formed whenever the two atoms joined are identical
polar bonds
bonds in which the electron density is unsymmetrical
matter
anything that has mass and occupies space
the three phases of matter
solid
fixed shape and volume
liquid
fixed volume but is not rigid in shape
gas
has neither a fixed volume nor shape
pure substances
fixed composition and a unique set of properties
mixtures
composed of two or more substances
element
a type of matter that cannot be broken down into two or more pure substances
compound
a pure substance that contains more than one element
electrolysis
involves passing an electric current through a compound, usually in the liquid state
mixture
contains two or more substances combined in such a way that each substance retains its chemical identity
homogeneous
or uniform mixtures are ones in which the composition is the same throughout (aka solution)
solution
made up of a solvent, usually taken to be the substance present in largest amount, and one or more solutes
heterogeneous
or nonuniform mixtures are those in which the composition varies throughout
filtration
used to separate a heterogeneous solid-liquid mixture
distillation
used to resolve a homogeneous solid-liquid mixture
mega
10^6
kilo
10^3
deci
10^-1
centi
10^-2
milli
10^-3
micro
10^-6
nano
10^-9
pico
10^-12
mass
a measure of the amount of matter in an object
weight
a measure of the gravitational force acting on an object
temperature
the factor that determines the direction of heat flow
significant figures
the meaningful digits obtained in a measurement
1 km
10^3m
1cm
10^-2m
1mm
10^-3m
1nm
10^-9m
1m^3
10^6cm^3
1cm^3
1mL
10^-3L
1cm^3
1kg
10^3g
1mg
10^-3g
1 mile
5280ft
intensive
independent of amount
extensive
depend on amount
chemical properties
observed when the substance takes part in a chemical reaction
physical properties
observed without changing the chemical identity of a substance
melting point
the temperature at which a substance changes from the solid to liquid state
boiling point
the temperature at which bubbles filled with vapor form within a liquid
Z
atomic number
A
mass number
atomic number
number of protons
mass number
number of prootons +number of neutrons
theoretical yield
the maximum quanityt that can be obtained under such conditions, assuming the reaction goes to completion and no product is lost
simplest formula
gives the simplest whole number ratio of atoms present
percent composition
the mass percents of the elements present
strong electrolytes
the solution conducts an electric current
nonelectrolytes
the solution does not conduct electricity
polyatomic ion
containing more than one atom
“charged molecule”
polyatomic ion
monatomic ion
derived from a single atom by the loss or gain of electrons
metals
have high electrical conductivities
metalloids
have electrical conductivities that are intermediate between those of metals and nonmetals
molecular formulas
represents molecular substances
structural formulas
represent the structures of molecules
condensed structural formula
suggests the bonding pattern in the molecule and highlights the presence of a reactive group of atoms within a molecule
atomic mass
atomic weight
nuclear symbol
shows the composition of a nucleus
acid
a species that produces H+ ions in water solutions
base
a species that produces OH- ions in water solution
strong acids
ionize completely, forming H+ ions and anions
strong base
is completely ionized to OH- ions and cations in water solution
weak acid
molecules containing an ionizable hydrogen atom (i.e. only partially ionized to H+ ions in water)
weak bases
react with H20 molecules, acquiring H+ ions and leaving OH- ions behind
amines
derivatives of ammonia in which one or more hydrogen atoms have been replaced by hydrocarbon groups
a common class of weak bases of the organic molecules
amines
strong acids and bases
are completely ionized in water
weak acids and bases
do not react completely
neutralization
when the H+ ions and OH- ions react with eachother to form H20 molecules
titration
measuring the volume of a standard solution required to react with a measured amount of sample
standard solution
a solution of known concentration
equivalence point
the point at which the reaction is complete
redox reaction
a reaction in aqueous solution that involves a transfer of electrons between two species
oxidation
an increase in oxidation number
reduction
a decrease in oxidation number
oxidizing agent
the ion or molecule that accepts electrons
reducing agent
the species that donates electrons

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