Final Review Flashcards
the more electronegative atom is assigned…
ALL the shared electrons
the less electronegative atom is assigned…
none of the shared electrons
each atom in a bond is assigned…
ALL of its unshared electrons
valence (e-) - [# shared (e-) + # unshared (e-) ] =
Oxidation Number
the charge an atom would have if all electrons were shared equally-- # of valence (e-) - (# unshared valence e- + 1/2# of shared e-)
Formal charge
*bonding electrons are shared equally by the atoms
the energy required to separate 1 mol of an ionic solid into gaseous ions; measure of the strength of an ionic bond
Also ~ (charge A x charge B) / distance
Lattice Energy
the # of electron pairs being shared by a given pair of atoms
= 1/2[(# e- in bonding MO) - (# e- in antibonding MO)]
Bond order (a single bond has 1 pair so BO = 1)
the energy needed to overcome the attraction between the nuclei and the shared electrons;
* the higher the bond energy the stronger the bond
Bond energy
*bond energy DECREASES down a group and INCREASES across a period
the distance between the nuclei of the bonded atoms
Bond length
*the shorter the distance the stronger the bond
bond length increases…
DOWN a group and…
bond length decreases…
ACROSS a period
the heat releases or absorbed during a chemical change is due to differences between the bond energies of reactants and products
deltaH(rxn) = sum[deltaH(reactant bonds broken)] + sum[deltaH(product bonds formed)]
ability of an atom to attract the shared electron pair
electronegativity
*atoms with lowest EN are placed in the middle
_______have the same relative placement of atoms but different locations of bonding and lone electron pairs
resonance structures
a species which can be depicted by more than one valid Lewis structure =
resonance hybrid
AXmEn
A = central atom
X = surrounding atom
E = nonbonding valence-electron group
(m and n are integers)
______have high IEs and highly negative EAs
*they tend to attract electrons strongly and form negative ions
Reactive nonmetals
______have low IEs and slightly negative EAs
*tend to lose electrons easily and form positive ions
Reactive metals
______have very high IEs nd slightly positive EAs
*they tend to neither gain or lose electrons
Noble gases
n =
orbital energy
positive intergers 1, 2, 3…
l =
orbital shape; positive integers from 0 to n-1
s, p, d, and f
m sub l =
integers from -l to 0 to l
m sub s =
electron spin direction
+ or - 1/2
the # of electrons lost or gained by an atom
Oxidation Number
- bonding electrons are transferred to the more electronegative atom
- always the same
the energy change that occurs when 1 mol of electrons is added to 1 mol of gaseous atoms or ions
Electron Affinity
- low EA–> form cations
- high EA–> form anions
the energy required for the complete removal of 1 mol of electrons from 1 mol of gaseous atoms or ions
*tends to DECREASE down a group and INCREASE across a period
Ionization energy
- low IE–> form cations
- high IE –> form anions (except noble gases)
theory that a covalent bond forms when the orbitals of 2 atoms overlap and a pair of electrons occupy the overlap region
the space formed by the overlapping orbitals can accommodate a max of 2 electrons with opposing spins
*the greater the overlap, the stronger the bond
Valence Bond Theory
A molecule is polar if…
it contains 1 or more polar bonds and
the individual bond dipoles do not cancel
anything that has both mass and volume
matter
the types and amounts of simpler substances that make up a sample of matter
composition
the characteristics that give each substance a unique identity
properties
properties a substance shows by itself without interacting with another substance, i.e. color, melting point, boiling point, density
physical properties
properties a substance shows as it interacts with or transforms into other substances, i.e. flammability, corrosiveness
chemical properties
has a fixed shape and volume
solid
has a varying shape that conforms to the shape of the container but a fixed volume; has an upper surface
liquid
has no fixed shape or volume and therefore does not have a surface
gas
the ability to do work
energy
the energy due to the position of an object
potential energy
the energy due to the movement of an object
kinetic energy
potential energy + kinetic energy
Total energy
1 degree Celsius =
1 Kelvin
1 degree Celsius/1 Kelvin =
1.9 degrees Farenheit
“The total mass of substances present does not change during a chemical reaction
Law of Conservation of Mass
If elements A and B react to form 2 compounds, the different masses of B that combine with a fixed mass of A can be expressed as a ration of small whole numbers
Law of Multiple Proportions
X =
Atomic symbol of the element
Z =
atomic number (# of protons in nucleus)
A =
mass number (A = Z + N)
N =
of neutrons in nucleus
atoms of an element with the same number of protons but a different number of neutrons
Isotopes
*they have the same Z# but different A #’s
the basic unit of an element or covalent compound consisting of 2 or more atoms bonded by the sharing of electrons
*most covalent substances consist of these
Molecule
a single atom or covalently bonded group of atoms that has an overall electrical charge
Ion
*Refer to formula mass, not molecular mass
Molecular mass =
sum of the atomic masses
*to 4 sig figs
the amount of substance that contains the same number of entities–(atoms, ions, molecules, electrons, formula units or any particle type)–as there are atoms in exactly 12 g of carbon-12
mole (mol)
–Avogadro’s # (N):
= 6.0222 x 10^23 entities (to 4 sig figs)
the mass of a substance per mole of its entities
Molecular mass
the simplest formula for a compound; shows the lowest whole # of moles and gives the relative # of atoms of each element present
Empirical formula
shows the ACTUAL # of atoms of each element in a molecule of the compound
Molecular formula
consists of 1 or more solutes dissolved in a solvent
solution
given by the quantity of solute present in a given quantity of solution;
expressed by ‘M’ = moles of solute/L of solution
concentration
Molarity
common compounds of group 1A (Li+ Na+ K+) NH4+ common nitrates (NO3-) acetates (CH3COO- or C2H3O2-) most perchlorates (ClO4-) common chlorides (Cl-), bromides (Br-), Iodides (I-) and common fluorides (F-) *except Pb2+, Ag+, Cu+ Hg2+ and group 2A common sulfates (SO2^2-) *except Ca2+ Sr2+ Ba2+ Ag+ and Pb2+
Soluble Ionic Compounds
all common metal hydroxides–except group 1A and larger members of group 2A beginning with Ca2+
all common carbonates (CO3^2-) and phosphates (PO4^3-)–except group 1A and NH4+
all common sulfides–*except group 1A, 2A and NH4+
Insoluble Ionic Compounds
a substance that produces H+ ions when dissolved in H2O
acid
a substance that produces OH- ions when dissolved in H2O
base
also called a neutralization reaction
acid-base reaction
the loss of electrons
oxidation
loses electrons and is oxidized
reducing agent
gains electrons and is reduced
oxidizing agent
the gain of electrons
reduction
electron transfer, oxidation and reduction occur together
a redox reaction
2 or more reactants combine to form a new compound: x + y –> z
combination reaction
z –> x + y
decomposition reaction
ab + cd –> ac + bd
double displacement
x + yz –> xz + y
single displacement
the process of combining with O2
Combustion
when orbitals of equal energy are available, the lowest energy electron configuration has the max # of unpaired electrons with parallel spins
Hund’s Rule
exhibits linear relationships among the variables of pressure, volume, temperature, and amount (moles)
idea gas
q (+) =
system GAINS heat
w (+) =
work done ON system
q (-) =
system RELEASES heat
w (-) =
work done BY system
1 kg * m^2 / s^2 =
1 J (joule)
1 calorie =
4.184 J
Enthalpy and chemical change:
deltaH = deltaE(q+w) + deltaPV = q
(deltaH ~ deltaE)
*for reactions without gases/where total moles don’t change/when q is much > deltaPV
q = c x m x deltaT
q- heat lost or gained
c - specific heat capacity
m- mass in grams
deltaT- T(final) - T(initial)
the enthalpy change of an overall process is the sum of the enthalpy changes of its individual steps
Hess’s law
deltaH overall = deltaH1 + deltaH2 +……+ deltaHn
cycles per second =
frequency
the distance a wave travels in one cycle
wavelength
the height of a wave crest or depth of a trough =
amplitude
the speed of light (c) is constant:
= 3.00 x 10^8 m/s (in a vacuum)
c = v x h
a solid object emits visible light when it is heated to about 1000K =
blackbody radiation
color is related to________ & _________
wavelength and frequency
temperature is related to __________
energy
E = nhv …
E = energy n = a positive integer h = Planck's constant v = frequency
It is not possible to know both the position and momentum of a moving particle at the same time
deltaX * m * deltaU >/= h/4pi
x = position
u - speed
Heisenberg’s Uncertainty Principle
*the more accurately we know the speed, the less accurately we know the position, and vice versa
Intensive
a physical property that doesn’t depend on the size or amount of material in the system/on outside variables (i.e. hardness)
extensive
a physical property that is proportional to the amount of material/size of system (i.e. mass and volume)
how contact lenses focus light
refraction
______
dispersion
separating through slits when an obstacle is met
diffraction
