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daltons atomic theory
1. all elements are composed of indivisible atoms
2. all atoms of a given element are identical
3. atoms of different elements are different
4. compounds are formed by the combination of atoms of different elements
jj thompson
cathode ray- electrons with negative charge
plum pudding
electrons spread out- positively charged with mass evenly distributed
gold foil- some alpha particles get deflected- atoms have a dense central core, called a nucelus, while the rest of the atom is empty space
bohr atom
dense nucleus with electrons found in surrounding circular orbits- electrons can move to different energy levels- also called planetary model- was not entirely supported
wave-mechanical model
atom has a dense, positively charge nucleus but the electrons, instead of beinng in definite, fixed orbits, had fixed amounts of energy moving in areas called orbitals
a region in which an electron of a particular amount of energy is most likey to be located
masses of subatomic particles
protons and nuetrons - 1amu
electrons- 1/1836 amu
what does each atom of a specific element need to contain
the same number of protons as each other atom of that element
atomic number
the number of protons in the nucelus of an atom
mass number
the sum of the number of protons and neutrons in an atom
atoms of the same element that have a different number of neutrons and different mass numbers
C-12 isotope, what does 12 represent
12 is the mass number
how do youy calculate the number of neutrons in an isotope
it is the difference between the atomic number of the atom and its mass number
atomic mass
average mass of all the isotopes in a sample of the element
ground state
when the electrons occupy the lowest availablee orbitals
excited state
when the electrons are subjected to stimuli such as heat, light,m or electricity, an electron may absorb energy and temproarily move to a higher energy level, which makes it in n unstable condition called an excited state
what happens to energgy when an electron moves up/down an energy level
up=gains energy
down=emits energy
(always a specific amount of energy)
what does the energy look like that is emitted from electrons
it comes in the form of infrared, ultraviolet, or visible light
what does visible light emitted by electrons look like
bright line spectra
how does the bright line spectra help us to identify elements
individual elements always have hte same lineson the bright line spectra
what determines the chemical properties of an atom
the arrangement of electrons- the number of electrons in the outer energy level of its atoms (aka the number of valence electrons)
principal quantum number
the same number as the number of the energy level that contains the electron
s, p, d, f
how many orbitals do the sublevels have?
s- one
p- three (px, py, pz)
d- 5 orbitals
f- seven orbitals
shape of s orbital
spherical shapes without sharp edges surrounding the nucelus
shape of p orbital
dumbbell shape at right angles
max number of electrons in each prinicipal energy level
1- 2
2- 8
3- 18
4- 32
where it is unlikely to find an electron
hunds rule
a single electron must be placed into each orbital of a given sublevel before any pairing takes place
what comes before 3d
what comes before 4d
uniform throughout- can contain more than one type of particle but particles are evenly mixed
are made up pf parts with different chemical and physical properties that are not uniformly mixed or dispersed
pure substance
its composition is the same throughout the sample
2 examples of pure substances
elements and compounds
substances that cannot be broken down or decomposed into simpler substances by chemical means
composed of two or more elements that are chemically combined in definite proportions by mass- is still the same composition throughout
law of definite proportions
types of atoms in a compound exist in a fixed ratio
combinations of two or more pure substances that can be separated by physical means
how are mixtures different from compounds
1. their composition is not deifnite or "fixed"; no ratio
2. can be separated by physical means
3. in a mixture, the parts contain their properties; do not in a compound (compound has its own properties)
what elements exist in nature as two identical atoms covalently vonded into a diatomic molecule
Br, I, N, Cl, H, O, F
qualitative info
relates to things that cannot be counted or measured
quantitative info
deals with things that can either be counted or measured
empirical formula
the simplest integer tatio in which atoms combine to form a compound
ionic formulas
indicate the ratio of the ions in a comound
units formed by covalently bonded substances
molecular formula
a multiple of the emprical formula
are not neutral-- are either negative or positive and the neg. and pos. attract each other and forms a ratio that produces a neutral compound
polyatomic ion
a group of atoms covalently bonded together, possessing a charge
how do compounds form
1. aatraction of oppositely charged ions
when wwater from some ioniic solutions evaporates, the solute forms a crystal lattice that binds water within the structure and forms a compound
what do the oxidation numbers correspond to
the group number (group one- 1+)
order of ions in a binary ionic compound
the positive first, then the negative
how to name binary ionic compounds
ex. NaCl
take the first ion
change the 2nd ion's ending to ide
sodium chloride
ex. MgS= magnisium sulfide
how to name other ionic ocompunds
if the metal is first, keep the name of the metal and the polyatomic ion
ex. KNO3= potassium nitrate

if the neg. is a nonmetal, the ending is -ide
ex. NH4Cl= ammonium chloride
binary covalent compound
contains 2 metals
how do you determine the order of compounds in a binary covalent compound
electronegativity- the one with the lower electronegativity is written first
how to name binary covalent compounds
ends in ide, but uses prefixes to tell how many atoms of each element are present
ex. CO- carbon monoxide
CO2- carbon dioxide
N2O4- dinitrogen tetroxide
stock system
used if a metal has more than one oxidation number
uses roman numerals to identify
physical changes
changes that do not result in the formation of a new substance, but only change in appearance
ex. phase changes
chemical changes
the identity of the products differs from the identity of the reactants
ex. bruning
processes that require energy in order to occur
-lowers surrounding temp. bc energy is abosrbed from the surroundings
-products have more potential energy than the reactants bc the reactants absorb energy as they become products
H2O(s) + energy---> H2O(l)
-processes that release thermal energy when they occur
-raises temp of surroundings bc energy is given off
-products have less potential energy than the reactants
x + y--> x + y + energy
law of conservation of mass
matter is neither created nor detroyed in chemical reactions- must be balanced
the 4 major types of reactions
1. synthesis (combination)
2. decomposition (analysis)
3. single replacement reactions
4. double replacement reactions
synthesis reactions
-when 2 or more reactants combine to form a product
A+B--> AB
-reverse of synthesis
-a single compund is broken down (decomposed) into two or more simpler substances
AB--> A + B
single replacement
where one element replaces another element in a compound
-always involves an element and a compound
-metals replace metals
A + BX --> B + AX
how do you know if a metal will replace another metal in a single replacement reaction/ a nonmetal reaplace a nonmetal
table j- a metal higher opn the table will replace a metal lower on the table/ a nonmetal higher up is more reactive and will reaplace a nonmetal lower on the table
double replacement reactions
generally involve two soluble ionic compounds that react in solution to produce a precipitate, a gas, or a molecular compound such as water
AB + CD --> AD + CB
3 ways you know if a double replacement reaction will occur
1. one product is a solid
2. one product is a gas
3. a molecular substance like water is formed
what is the masss of an atom in AMU relatively based on
the mass of a carbon-12 atom (amu- 12)
formula mass
the sum of the atmic masses of all the atoms present (the number of atoms of each elemnt mutiplied by the amu, then add all together)
gram formula mass
in grams instead of amu
(also gram molecular mass if the elements form molecules)
percentage composition
the composition of a percentage of each element compared with the total mass of the compound
how to find percent composition
find the formula mass
divide the mass of the element you are trying to find by the formula mass, and mltiply by 100
srystals that contain attached water molecules
avogadros number
the number of particles in a mole of a substance
6.02 x 10^23
the number of atoms of carbon pressent in 12 grams of c-12
gram formula mass & moles
the gram formula mass of any substance is the mass of one mole of that substance
how to convvert grams to moles
moles= number of grams x 1 mole
gram mass form
how to convert moles to grams
grams= number of moles X
gram mass form
1 mole
solid phase
-definite volume and shape
-rigid form
-crystalline stucture
liquid phase
-not as rigid as solid phase
-particles move past each other
-no definite shape, but deifnite volume
gaseous phase
-noo much attraction
-no definite volume or shape
-spread out
why does temp remain constant in heating and cooling curves even though heat is being added
the heat is bsorbed in the form of potential energy- used to break bonds
on a curve, when are two phases present
when the line is straight and temp is not increasing
reverse opf boiling
solid changes directly to a gas
gas changes directly to a solid
measure of kinetic energy
which way does heat flow
from higher temp to the lower temp until the 2 are the same temp
how to determine freezing and boiling points
the freezing point/boiling ppoint of a substance is the equilibrium temperature of the two phases
how to find kelvin
celcius + 273
used to measure the amount of heat given off in a reaction
heat of fusion
the amount of heat needed to convert a unit mass of a substance from a solid to liquid at its melting point
HEAT OF vaporization
the amount of heat needed to convert a unit mass of a substance from its liquid phase to its vapor phase at constant temp
kinetic molecular theory
used to explain gases:
1. gases contain particles that are n constant, random, straight-line motion
2. gas particles collide with each other and with the wallsof the cnotain- energy is tranfered but not lost- elastic
3. gas partciles are separated- the volume occupied by the particles themselves is negligible
4. gas particles do not attract to eahc other
what happens to the pressure if more gas particles are added
increase- directy proportional
what happens to the pressure of a gas if you increae the volume
pressure decreases- indirectly related
temp and volume relationship of a gas
as temp increases, volume increases
-directly related
temp and pressure relationship of a gas
as temp increases, pressure increases
-directly related
relationship of temp and velocity of a gas
as temp increases, velocity increases
2 things about the knetic molecular theory that is not completely correct bc it talks about ideal gases
1. gas particles do not attract each other- there is small attraction sometimes
2. gas particles do not occupy volume- as pressure increases the volume can no longer be ignored
what 2 gases are nearly ideal
hydrogen and helium
why do gases vary from ideal behavior
1. increasing mass
2. increasing polarity
where as gases most ideal
at low pressures and high temperatures
what are a few ways the components of a mixture can be separated?
density, molecular polarity, freezing point, and boiling point
two liquids that are not soluble in each other
can separate the mixture of a solid in a liquid or se[arate solids and gases
separatory funnel
separates two liquids by density
can separate homogenous solutions of solids dissolved in liquids - separate by boiling points
when liquids mix with each other
can separate mixtures
what can be separated with a paper filter
a solid in a liquid
how is gasoline separated into its components
fractional distillation
what is the principal that allows paper chrmatography to separate mixtures
components having differnet attractions to the paper
how did mendeleev first putthe periodic table
in order of increasing atomic mass
how is the periodic table now set up
by increasing atomic number
henry moseley
used x-rays to identify the atomic number of the elements
periodic law
the properties of the elements are periodic functions of their atomic numbers
horizontal rows on the table
what does the number at the beginning of hte period indicate
the principal energy level in which the valence electons are located
properties in the period
properties change across the period
have some properties of metals and some of not metals
located 4 horizontal from group 13, with 2 in 14 and 2 in 15
in what phase are metals and metalloidsa
all solid except mercury
what phases are nonmetals in
all 3
vertical columns
what does each memeber of a given group contain, with a few exceptions
the same number of valence electrons, and therefore similar chemical properties
where are the most active metals located
in group 1 and 21
how do metallic properties increase
in any group, the metallic properties of the elements increase from the top to the bottom of the group
what are some general properties of metals
1. solid at room temp except mercury
2. most have densities greater than water, except group 1
3. malleable- can be hammered into shape
4. ductile
5. have luster
6. good conductors of heat and electricity bc of the mobility of their valence electrons
7. have low ionization energy and low electronegavity
8. tend to lose electrons to form positive ions with smaller radii
what is group 1 called
alkali metals
transition elements
group 3-group 12
typically hard solids with high melting points
multiple oxidation states
often forms ions that have color
properties of nonmetals
1. many are gases or solids at room temp
2. not malleable or ductile- are brittle in solid phase
3. no luster- dull surface
4. high ionization energy and high electronegativity
5. poor conductors fo heat and electricity
6. tend to gain electrons to become negative ions with radii larger than their atoms
what is a element with more vvalence electrons most likely to do
to gain electrons, forming a positive negative ion
noble gases
the elements in group 18
-are genreally unreactive bc they have completely filled outer energy level, which makes them stable
some nonmetals can consist of two or more forms in the same phase
ex. O2 (oxygen) and O3 (ozone)
how are allotropes different
different phsical and chemical proeprties
where is the highest electronegavity on the table
top right
ionization eergy
the amount of energy needed to remove the most loosely bound electron from a neutral gaseous atom
ionization energy and trends in a period
values increase across a period from left to right
ionization trend in a group
decreaes from top to bottom bc the valence electrons are at higher energy levels and are thus farther from the nucleus- it is easier to remove them when they are farther away
atomic radius trends in a period
from left to right, there is a repeating pattern of decreasing atomic radii (number of protons increase and pulls in electrons, causing decreasing atomic radius)
atomic radius and groups
atomic radius increases from top to bottom (more inner level electrons shield the valence electrons from the protons in the nucleus)
ionic radius
distance from hte nucleus to the outer energy level of the ion
-metallic ions are smaller bc it loses electrons when it becomes positive
electronegativity trends on the table
-highest electronegativity on the top of the group
-increases from left to right on the periods
what 3 groups have elements so reactive they cant be found in the free or uncombined state
groups 1, 2, and 17
propertie of hydrogen
-not in a group
-can form ionic compounds and covalent compounds
what are elements in group 1 called
alkali metals
what are the elements of group 2 called
alkaline earth metals
properties of groups 1 and 2
easily lose their electrons
always found in compounds, not alone
-low ionization and electronegativity
when is the only time that oxygen has a positive oxidation value
when it vonds to the only element more electronegative than itself
what is group 17 called
when atoms of elements in group 17 gain an electron, they get a 1- charge and the salts formed are called halides
what is the only group that has 3 states of matter at room temp
group 17- halogens
what is the rule about electrons and boiling points in nonpolar mmolecules
more electrons= higher melting and boiling points
less electrons=lower melting points and boiling points
what element comes first when forming a compound
the only that loses the electrons comes first
what kind of process is the breaking of a chemical bond
endothermic- energy is required to break a bond
what kinwhat kind of process is the formation of a bond
exothermic- breaking a bond releases energy
when a chemical bond is formed, does the formed compound have more or less potential energy than the substances from which is was formed
less potential energy bc energy is always released when a ond is formed
stability vs. energy
the greater the energy released during the formation of a bond, the greater its stability
the alll of an atoms nonvalence electrons
atoms with a double bond
atoms with atriple bond
boiling and metal points of metals
metallic bonding
results from the force of attraction of the mobile valence eletrons for an atom's positively charged kernel
what term is used to describe metallic bonding and why
"sea of mobile electrons" - freedom of valence electrons
where does metal bonding occu
between metal atoms that have vacant valence orbitals and low ionization energies
crystalline lattice
max number of valence electrons that an atom can have
octet rule
atoms generally react by gaining, losing, or sharing electrons in order to get 8 valence electrons
covalent bond
formed when two nuclei share electrons in order to achieve a stable arrangement of electrons
-formed between two nonmetal atoms of the same element
non polar covelent ond
attraction is equal- between two atoms of the same element - having equal or close electronegativity
multiple covalent bond
when atoms share more than one pair of electrons (double and triple covalent bonds)
polar bond
unequal sharing of electrons
in a polar bond, which atom pulls harder
one with the high electronegativity
in a polar bond, which atom has the pos. charge and which has the neg. charge
higher electronegativity attracts electrons more strongly, making that negative, and the lower electronegativity positive
smallest discrete particle of an element or compound formed by covalently bonded atoms
properties of a molecule
soft, poor ocnductors of heat and electricity, and low melting and boiling pts
-can be solids, liquids, or gases
what happens when metallic atoms react
1. lose electrons
2. become pos. charged ions
3. acquire a configuration that has a complete octet of electrons
4. their radii decrease
what happens when nonmetallic atoms react
1. they gain electrons
2. they become negatively chared ions
3. they acquire a complete octet of electrons
4. their radii increase
polarity and electronegativity
as the electronegativity difference between two atoms in a bond increases, the bond becomes more polar in nature
electronegativity and the type of bond
if the difference in electronegativity is -1.7 OR GREATER-, the bond is ionic
if the difference in electronegativity is less than that, it is covalent
what do all compouns with polyatomic ions contain
both ionic and covalent bonds
melting and boiling pts of metallic, covalent, and ionic bonds
metallic- high
ionic- high
covalent- low
bonds and conductivity
metallic- good electrical and thermal conductivity
ionic- bad (unless melted)
covalent- bad
hardness of 3 bonds
ionic- hard
metallic- hard
covalent- soft
polar molecules (bc they have positive and negative ends)
when is the only time ionic molecules have good conductivity
in liquid and aqeuous states
dipole-dipole forces
when the positive area of one dipole molecule is attracted to the negative portion of an adjacent dipole molecule
hydrogen bond
an intermolecular bond between a hydrogen atom in one molecule and a nitrogen, oxygen, or fluorine atom in another molecule
where is hydrogen bonding specifically founbd
why does water have a high boiling pt.
hydrogen bonding- stronger than dipole-dipole attraction
why does hydrogen only bond with nitrogen, oxygen, and fluorine
they are highly electronegative and have small radii
homogenous mixture of substances in the same physical state- can contain atoms, ions, or molecules of o
when metals are mixed to form a solution
the substance that is being dissolved; present in the smaller amount
the substance that dissolves and is the greater amount
what is the most common solvent
properties of solutions
1. homogenous mixtures
2. clear and do not disperse light
3. have color
4. will not settle on stnading
5.will pass through a filter
how does NaCl dissolve in water
pos. Na is attracted to the neg. part of the water and the neg. Cl is attracted to the pos. part of hte water
like dissolves like
yea- but ionic is insoluble in nonpolar solvent and soluble in polar solvent
temp and solubility
-as temp increases, most solids become more soluble in water
- as temp increases, the solubility of gases decrease
pressure and solubility
pressure has little or no effect on the solubility of solid or liquid solutes
-incrases the solubility of gases in liquids (ex. soda can is oopened- press decreases and carbon dioxide escapes as bubbles bc it is no longer as soluble at thelowered press)
if something is not soluble, what happens when it forms
it forms as a precipitate
howcan u tell if something is saturated
1. if the solution contains some undissolved solute
2. if you add a solute crystal and it dissolves, the orginial solution was unsatured; if it just falls to the bottom, it was saturated; if additinal crystals form, it was supersaturated
the number of moles of solute in 1 L of solution
percent mass
mass of part
----------- x 100
mass of whole
percent by volume
volume of solute
---------------- x 100
volume of solution
what happens when u add salt to water
it lowers the freezing point of water
one mole of anything will lower the freezing point of water
why do ionic substances lower the freezing of water more than a molecular substance
bc when a molecular substance dissolves in water, oone mole of its particules is producted- ionic compounds break into ions so there are more moles
one mole of anytihng will raise the boiling pt of water
substance that is normally a solid or a liquid at room temp enters the gas phase
vapor pressure
as the temp of a liquid increases, the particles have more energy, and more particles escape from the surface- these vapor particles are gaseous particles and exert pressure in the gaseous phase
what does it mean if a gas exerts less vapor pressure
it has stronger intermolecular foces holding it in the liquid phase
when does a gas vaporize
when the vapor pressure equals the atmospheric pressrue
heatof vaporization
the heat required to change 1 mol ofa substance from a liquid at its boiling point to 1 mole of a vapor
what happpens to the boiling pt of water if you increase atmosperic pressure
the boiling pt increases
factors that affect rate of reaction
1. nature of the reactants
2. concentration
3. surface area
4. the presence of a catalyst
5. temp.
nature of the reactants
covalent bonds are slower to react than ionic substance bc of the number of nods that must be broken- needs more energy
increase in concentration causes a faster rate bc there are more collisions
surface area
more surface area=more chances of collision=faster reaction rate
substance that increaes the rate of a reaction by providing a different and easier pathapay for reaction
increaes temp==faster molecules=more collisions and more energy=faster
sum up of factors
increasing all of them increaes the rate
what must happen in order for a reaction to occur
the reactants must have sufficient energy to collide effectively and they must be properly positioned
activiated complex
temporary, intermediate product thatmay either break apart and reform the reactants or rearrange th atoms and form new products
on a potential energy diagram, what is any line that begins at the orgin of the y-axis
a measure of PE
activation energy
the amount of energy needed to form the activated complex from the reatctants
heat of reaction (delta H)
the difference between the potential energy of the reactants and the potential energy of the products
what do catalysts do to teh diagram
lower the activiation energy
endothermic diagram
higher pe at the end
exothermic diagram
lower pe at the end
when both forward and reverse reactions occur at the same time- a state of balance between the rates of two opposite processes that are taking place at the same rate
common misconceptation about equilibrium
the products and reactants dont have to be equal, but the rates of the forward and reverse reactions have to be equal
phase equilibrium
melting points and freezing points- solid and liquid phases in closed and open containers
solution equilibrium
dissolving and recristalization are equal- equilibrium exists, solution is saturated
le chateliers principle
a system at equilibrium responds to relive stress on the system
any change in temp, concentration, or pressure on an equilibrium system
concentration changes
if you increase one reactant, the other reactant will decrease and the products will increase- it will shift to the right

-if you decrease one reactant, the other reactant will increase and the products will decrease- shift to the left
temp changes
if you raise the temp of one reactant, you raise the temp of the other and lower the temps of the two products and produce more heat (favors endothermic reaction)
-if you lower the temp of one reactant, you lower the temp of the other reactant, increae the temp of the products, and decrease the heat released
(favors exothermic reaction)
pressure changes
(does not affect rate of solids and liquids, but affects rate of gases)
-if pressure is added to the reacants, the system will shift to the right
-if pressure is decreased from hte reacants, the system will shift to the left
what if both sides are gaseous
an increase in pressure will favor the reaction toward the side with fewer gas molecules
-a decrease in pressure favors the reaction toward the side with the greater number of gas molecules
effect of a catalyst oon shifts
changes reates equally- doesnt shift

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