March 2015
march 25, 2015
Shapes
Linear 180 2 or 3 atoms
Bent 104.5 3 atoms
Trigonal
planar 120 4 atoms
Trigonal
pyramidal 107.3 4 atoms
Tetrahedral 109.5 5 atoms
march 17, 2015
Valance electrons
The electrons in the highest occupied energy level of the atom
The number of valance electrons determines the chemical properties of the element
Electron dot (Lewis Electron Dot) Structure
An elements atomic symbol surrounded by the number of valance electrons in the element
Octet Rule
Atoms in compounds tend to have the electron configuration of a noble gas (8 outermost electrons)
Cation
An atom that loses valence electrons to satisfy the octet and acquires a positive charge
Anion
An atom that gains valence electrons to satisfy the octet and acquires a negative charge
Ionic Compounds
A compound composed of positive and negative ions
Ionic bond
The electrostatic attraction that binds oppositely charged ions together
Coordination number
The number of oppositely charged ions that surround an ion in a crystal
Properties of ionic compounds
- high melting point
-conducts electricity when dissolved in water or melted
-crystal structure
-hard
-brittle
Metallic bonds
The attraction of free-floating valence electrons for positively charged metal ions (cations).
Properties of metals
- malleable
-conduct heat and electricity
-high melting points
-strong
march 13, 2015
Periodic Trends
Atomic Radius
The term used to describe the size of the atom.
The atomic radius of an atom decreases as you move left to right across a period and increases as you
move from top to bottom down a group.
Ion
An atom that acquires a charge by losing or gaining electrons.
Ionization energy
The energy needed to remove an electron from an atom.
The ionization energy of an atom increases as you move left to right across a period and decreases as you
move top to bottom down a group.
Electronegativity
An atoms ability to attract electrons while in a chemical bond. Electronegativity increases left to right across a period and decreases top to bottom down a group.
All three periodic trends can be explained using the same reasoning
As you move across a period from left to right each atom has one proton and one electron more than the previous atom. The protons are added to the nucleus increasing the nuclear charge. The electrons are added to the same energy level as you move across a group. All the electrons in the period(energy level) have the same distance from the nucleus.
As you move down a group from top to bottom you are adding energy levels with each step down. The nuclear distance is increasing with each step down a group.
*** Nuclear attraction increases left to right across a period and decrease top to bottom down a group due to the distance between the nucleus (+) and the outermost electrons(-) and the addition of protons and electrons.
Shielding effect
Inner (core) electrons shield the outermost electrons from the nuclear attraction.
march 2, 2015
ATOMIC STRUCTURE REVISITED
99% OF ALL CHEMISTRY CAN BE EXPLAINED BY THE ARRANGEMENT OF THE ELECTRONS IN THE ATOMS, IONS OR MOLECULES
Neils Bohr electrons have energy (E)
The Bohr Atom
a) There is a nucleus (this was Rutherford's discovery).
b) The electrons move about the nucleus in "orbits" also called energy levels or shells.
c) When an electron moves from one energy level to another, the energy lost or gained is done so ONLY in very specific amounts of energy. These specific amounts of energy are called quanta. The energy is said to be quantized.
d) Specific spectra (light energy) are absorbed or released when an electron moves from one energy level to another.
e) Each element absorbs or releases spectra that are specific for that element and therefore can identify the element.
MAX PLANCK
MATTER CAN LOSE OR GAIN ENERGY IN SMALL, SPECIFIC AMOUNTS CALLED QUANTA
QUANTUM
THE AMOUNT OF ENERGY NEEDED TO MOVE AN ELECTRON FROM ITS PRESENT ENERGY LEVEL TO THE NEXT HIGHER ENERGY LEVEL
Eq=hγ
Eq=ENERGY OF A QUANTUM H= PLANCKS CONSTANT γ= FREQUENCY
LIGHT
ENERGY THAT TRAVELS IN WAVES.
WAVES
A DISTURBANCE THAT CARRIES ENERGY
ELECTROMAGNETIC RADIATION
waves that travel at the speed of light (3.0 x 1023 m/sec) and can travel in any medium including a vacuum.
WAVELENGTH
THE HORIZONTAL DISTANCE BETWEEN TWO IDENTICAL POINTS ON TWO ADJACENT WAVES
FREQUENCY
the number of waves that pass by per second. Frequency is usually measured in Hertz (cycles/sec)
AMPLITUDE
Amplitude is the distance from the rest position to the crest position which is half the vertical distance from a trough to a crest
SPECTROSCOPE
INSTRUMENT USED TO MEASURE THE WAVELENGTH OF VISIBLE LIGHT
ELECTRON CONFIGFURATION
THE WAYS IN WHICH THE ELECTRONS ARE ARRANGED AROUND THE NUCLEUS
PHOTON
A QUANTUM OF LIGHT ENERGY
RULES FOR ELECTRON CONFIGURATION
1) AUFBAU PRINCIPLE: ELECTRONS WILL ALWAYS OCCUPY THE LOWEST ENERGY ORBITALS AVAILABLE.
2) PAULI EXCLUSION PRINCIPLE: A MAXIMUM OF 2 ELECTRONS (WITH OPPOSITE SPINS) CAN OCCUPY AN ORBITAL.
3) HUND'S RULE: FOR EQUAL ENERGY ORBITALS, ELECTRONS WILL OCCUPY EACH ORBITAL BEFORE PAIRING UP
NOBEL GAS (SHORTCUT) ELECTRON CONFIGURATION IS DONE BY FIRST WRITING THE PREVIOUS NOBEL GAS IN PARANTHESES, FOLLOWED BY THE REMAINING ELCTRON CONFIGURATION.
VALENCE ELECTRONS:
THE ELECTRONS IN AN ATOMS OUTERMOST ORBITALS. VALENCE ELECTRONS DETERMINE THE ELEMENTS CHEMICAL PROPERTIES.
LIGHT
ENERGY THAT TRAVELS IN WAVES.
ALSO CALLED ELECTROMAGNETIC RADIATION
ELECTROMAGNETIC RADIATION
WAVES THAT DO NOT NEED A MEDIUM TO TRAVEL AND TRAVEL AT THE SPEED OF LIGHT (3.0 X 10^23 METERS PER SECOND) IN A VACUUM.
RADIATION
THE EMISSION OF ENERGY AS ELECTROMAGNETIC WAVES
WAVES
A DISTURBANCE THAT CARRIES ENERGY
WAVELENGTH
THE DISTANCE BETWEEN TWO IDENTICAL POINTS ON TWO ADJACENT WAVES
FREQUENCY
THE NUMBER OF WAVES THAT PASS THROUGH A SPECIFIC AREA PER SECOND
SPECTROSCOPE
INSTRUMENT USED TO MEASURE THE WAVELENGTH OF VISIBLE LIGHT
ELECTROMAGNETIC SPECTRUM
THE RANGE OF ALL POSSIBLE FREQUENCIES OF ELECTROMAGNETIC RADIATION
ENERGY LEVELS
A REGION AROUND THE NUCLEUS OF THE ATOM WHERE THE ELECTRON IS MOVING.
GROUND STATE
THE LOWEST ENERGY LEVEL OCCUPIED BY AN ELECTRON. THE MOST STABLE STATE OF THE ATOM.
EXCITED STATE
AN ENERGY LEVEL HIGHER THAN THE GROUND STATE
ATOMIC EMISSION
FREQUENCIES OF ELECTROMAGNETIC RADIATION EMITTED DUE TO AN ATOM'S TRANSITION FROM A HIGHER ENERGY LEVEL TO A LOWER ENERGY LEVEL
complete questions 12 to 19 on the last page of the quarterly review
Ideal and combined gas Law
March 25, 2014
Polarity
The state of having two opposite poles. One positive (or slightly positive) and one negative (or slightly negative.
Polar Bond
A covalent bond in which the
electrons are not shared equally.
This creates a bond in which one side is more positive and the other side is more negative.
Dipole
Having two poles
Polar Molecule
A molecule that has a
positive and negative end due to its' polar bonds and it's molecular geometry.
Intramolecular forces are the attractive forces that hold atoms or ions together within ionic compounds, molecules or metals. Examples are covalent bonds, ionic bonds and metallic bonds.
Intermolecular forces are the attractive forces that bond molecules to other identical molecules.
Intramolecular forces are much stronger than intermolecular forces
Intermolecular forces
Van der Walls Forces
1) dispersion forces-weakest of all intermolecule forces.
Caused by the motion of electrons
animation
2) dipole-dipole forces- attraction of a polar molecule to another polar molecule
animation
Hydrogen bonds
a hydrogen bonded to a very electronegative atom bonds weakly to an unshared electron pair on a similar molecule. Hydrogen bonds are the strongest of the intermolecular forces
animation
Kinetic molecular theory
The tiny particles (atoms,molecules) in all forms of matter are in constant motion.
The Gas Laws
Boyle's Law
The volume of a fixed amount of gas,at constant temerature, varies inversely with the pressure
P1 x V1 =P2 x V2 = constant
Charles Law
The volume of a fixed amount of gas, at constant pressure, is directly proportional to its Kelvin temperature
V1 = V2 = constant
T1 T2
Gay-Lussac's Law
The pressure of a fixed amount of gas, at constant volume, is directly proportional to the Kelvin temperature
P1 = P2 = constant
T1 T2
Kelvin temperature scale
the temperature scale in which the freezing point of water is 273K and the boiling point is 373K. 0K is absolute zero.
The Combined Gas Law
A single law that states the relationship between pressure, volume and temperature of a fixed amount of gas.
P1 x V1 = P2 x V2
T1 T2
animation
STP (Standard temperature and pressure)
the conditions in which the volume of a gas is often measured; standard temperature is 0 celsius, standard pressure is 1 atm
animation
March 19, 2014
students took test
Shapes of Molecules
VSEPR Theory:
Atoms in a molecule will arrange in the shape that best minimizes the repulsion of their shared and unshared valence electrons pairs.
Because electron pairs repel, molecules adjust their shapes so that the valence electron pairs are as far apart as possible.
Shared Electron Pairs
Valence electrons that are involved in a covalent bond
Unshared Electron Pairs
Valence electrons that are not involved in a covalent bond
Shapes
Linear 180 2 or 3 atoms
Bent 104.5 3 atoms
Trigonal
planar 120 4 atoms
Trigonal
pyramidal 107.3 4 atoms
Tetrahedral 109.5 5 atoms
coordinate covalent bond
covalent bond in which both shared electrons are donated by the same atom
Resonance
when two or more electron dot structures can be written for the same compound
molecular (covalent ) compound
compound made up of two or more nonmetals that are covalently bonded together into a molecule.
Covalent Bond
A chemical bond that results from the sharing of valence electrons
A molecule is formed when two or more atoms bond covalently
Single Covalent Bond
A bond in which two electrons are shared by two atoms
Double Covalent Bond
A bond in which four electrons are shared by two atoms
Triple Covalent Bond
A bond in which six electrons are shared by two atoms
coordinate covalent bond
covalent bond in which both shared electrons are donated by the same atom
Resonance
when two or more electron dot structures can be written for the same compound
March 20,2013
Blocks 1A,2A,4A
Students began the class with a lab that explored the behavior of gases.
The Gas Laws
Boyle's Law
The volume of a fixed amount of gas,at constant temerature, varies inversely with the pressure
P1 x V1 =P2 x V2 = constant
Charles Law
The volume of a fixed amount of gas, at constant pressure, is directly proportional to its Kelvin temperature
V1 = V2 = constant
T1 T2
Gay-Lussac's Law
The pressure of a fixed amount of gas, at constant volume, is directly proportional to the Kelvin temperature
P1 = P2 = constant
T1 T2
Kelvin temperature scale
the temperature scale in which the freezing point of water is 273K and the boiling point is 373K. 0 K is absolute zero.
animation
The Combined Gas Law
A single law that states the relationship between pressure, volume and temperature of a fixed amount of gas.
P1 x V1 = P2 x V2
T1 T2
animation
gas_laws_mixed_ws_3.pdf | |
File Size: | 65 kb |
File Type: |
March 19,2013
Blocks 1B,5B
Students began the class with a lab that explored the behavior of gases.
The Gas Laws
Boyle's Law
The volume of a fixed amount of gas,at constant temerature, varies inversely with the pressure
P1 x V1 =P2 x V2 = constant
Charles Law
The volume of a fixed amount of gas, at constant pressure, is directly proportional to its Kelvin temperature
V1 = V2 = constant
T1 T2
Gay-Lussac's Law
The pressure of a fixed amount of gas, at constant volume, is directly proportional to the Kelvin temperature
P1 = P2 = constant
T1 T2
Kelvin temperature scale
the temperature scale in which the freezing point of water is 273K and the boiling point is 373K. 0 K is absolute zero.
animation
The Combined Gas Law
A single law that states the relationship between pressure, volume and temperature of a fixed amount of gas.
P1 x V1 = P2 x V2
T1 T2
animation
March 18, 2013
Blocks 1A,2A,4A
Kinetic Molecular Theory
The states of matter, and much of the behavior of matter, can be explained by the concept that all forms of matter are in constant motion
Temperature
the measure of the kinetic energy of the molecules of a substance
Diffusion
tendency of molecules to move toward areas of lower concentration untill concentration is uniform
Effusion
when molecules escape through tiny holes in a container
Graham's Law of Effusion or Diffusion
The rate of effusion or diffusion of a gas is inversely proportional to the square root of its molar mass
Pressure is force per unit area.
P= f/a
Gas pressure
The pressure created by the collisions of the gas particle with the walls of the container the gas is kept in.
Atmospheric Pressure
Pressure exerted by the gas particles in the atmosphere.
Barometer
Instrument used to measure atmospheric pressure
monometer
Instrument used to measure the pressure of a contained gas
Units of pressure
101.3 kpa = 760 mmHg = 1 atm
Daltons Law of Partial Pressure
at constant volume and temperature, the total pressure of a mixture of gases is equal to the sum of the partial pressures of all the gases present.
Ptotal = P1 + P2 + P3 + ....
The Gas Laws
Boyle's Law
The volume of a fixed amount of gas,at constant temerature, varies inversely with the pressure
P1 x V1 =P2 x V2 = constant
Charles Law
The volume of a fixed amount of gas, at constant pressure, is directly proportional to its Kelvin temperature
V1 = V2 = constant
T1 T2
Gay-Lussac's Law
The pressure of a fixed amount of gas, at constant volume, is directly proportional to the Kelvin temperature
P1 = P2 = constant
T1 T2
Kelvin temperature scale
the temperature scale in which the freezing point of water is 273K and the boiling point is 373K. 0K is absolute zero.
The Combined Gas Law
A single law that states the relationship between pressure, volume and temperature of a fixed amount of gas.
P1 x V1 = P2 x V2
T1 T2
March 15, 2013
Blocks 1B,5B
Kinetic Molecular Theory
The states of matter, and much of the behavior of matter, can be explained by the concept that all forms of matter are in constant motion
Temperature
the measure of the kinetic energy of the molecules of a substance
Diffusion
tendency of molecules to move toward areas of lower concentration untill concentration is uniform
Effusion
when molecules escape through tiny holes in a container
Graham's Law of Effusion or Diffusion
The rate of effusion or diffusion of a gas is inversely proportional to the square root of its molar mass
Pressure is force per unit area.
P= f/a
Gas pressure
The pressure created by the collisions of the gas particle with the walls of the container the gas is kept in.
Atmospheric Pressure
Pressure exerted by the gas particles in the atmosphere.
Barometer
Instrument used to measure atmospheric pressure
monometer
Instrument used to measure the pressure of a contained gas
Units of pressure
101.3 kpa = 760 mmHg = 1 atm
Daltons Law of Partial Pressure
at constant volume and temperature, the total pressure of a mixture of gases is equal to the sum of the partial pressures of all the gases present.
Ptotal = P1 + P2 + P3 + ....
March 8, 2013
Blocks 1A,2A,4A
Mr Coppola was absent today and the substitute teacher distributed several worksheets that were to be completed in class. Any work that was not completed in class was assigned as homework.
March 7, 2013
Blocks 1B,5B
Students worked on mass to mass stoichiometry problems.
Students then performed a stoichiometry lab and witnessed a stoichiometry demonstration. Students then caculated the theoretical outcome of both the lab and demonstration.
Limiting Reactant
The reactant that is used up first in a chemical reaction. The limiting reactant determines the amount of product that can form.
Excess Reactant
The reactant that is present in a quantity that is more than enough to react with the limiting reactant.
March 6, 2013
Blocks 1A,2A,4A
Students finished the stochiometry lab and compared their results to the theoretical yield of the experiment.
Theoretical Yield
The amount of product that could form during a chemical reaction. Theoretical yield is calculated from a balanced chemical equation.
Actual Yield
The amount of product that is formed when a reaction is carried out
Percent Yield
The ratio of the actual yield to the theoretical yield expressed as a percentage; a measure of the efficiency of a reaction
Percent Yield = actual yield x 100
theoretical yield
Limitng Reactant
The reactant that is used up first in a chemical reaction. The limiting reactant determines the amount of product that can form.
Excess Reactant
The reactant that is present in a quantity that is more than enough to react with the limiting reactant.
March 5, 2013
Blocks 1B,5B
Students worked on mass to mass stoichiometry problems.
Students then performed a stoichiometry lab and witnessed a stoichiometry demonstration. Students then caculated the theoretical outcome of both the lab and demonstration.
Limiting Reactant
The reactant that is used up first in a chemical reaction. The limiting reactant determines the amount of product that can form.
Excess Reactant
The reactant that is present in a quantity that is more than enough to react with the limiting reactant.
March 4, 2013
Blocks 1A,2A,4A
Students worked on mass to mass stoichiometry problems.
Students then performed a stoichiometry lab and witnessed a stoichiometry demonstration. Students then caculated the theoretical outcome of both the lab and demonstration.
Limiting Reactant
The reactant that is used up first in a chemical reaction. The limiting reactant determines the amount of product that can form.
Excess Reactant
The reactant that is present in a quantity that is more than enough to react with the limiting reactant.
March 1,2013
Blocks 1B, 5B
Students worked on another mole to mole stochiometry worksheet. We then introduced mass to stochiometry and students worked on a mass to mass worksheet and started a stochiometry lab. Both worksheets can be downloaded below.
stoichiometry_mass_ws.pdf | |
File Size: | 90 kb |
File Type: |
mole-mole_stochiometry_ws.pdf | |
File Size: | 95 kb |
File Type: |