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Chemistry Review for Final Exam
Isomers
Same molecular formula, different structureDraw 2 isomers with the formula C4 H10
Bonds
Octet RuleIonic : metal & nonmetal; electrons
transferredCovalent: 2 non-metals; electrons are shared
Single Double Triple
Electron Configuration
Maps the location of the electrons around the nucleus
1s2 2s2 2p6 3s1 Which element?What’s the valence shell?Which energy level is completely full of
electrons?
Electron Configuration
Aufbau Principle Lowest energy levels fill first
Pauli Exclusion Principle 2 electrons in the same energy level have separate
spinsHund’s Rule
In energy levels with multiple orbitals, one electron goes in each orbital FIRST then additional ones (up to 2 in an orbital) are added
Draw the Aufbau diagram for carbon
3s2p
2s1s
Periodic Table Trends
IE: Ionization energy-the amount of energy needed to take an electron from an atom increase across decrease down
AS (Atomic Size) decrease across because of shielding increase down
EN (Electronegativity-the ability of an atom to take an electron from another. ) Higher in non metals Increase across decrease down
The Mole
The mole highway!
How many moles are in 3.4g of LiCl?
How many liters are in 58g of steam (H2O)?
Chemical and Physical Changes
Chemical change: results in a rearrangement or a recombination of atoms, different from the reactants. Cooking an egg Burning wood Baking a cake
Physical change: atoms have not been rearranged Boiling water Tearing paper Breaking glass Dissolving sugar in water
Endothermic and Exothermic
Endothermic: heat is absorbed by the system An egg absorbs heat as it cooks A scoop of ice cream absorbs heat as it melts An ice cube melts
Exothermic: heat is released Nuclear fission Nuclear fusion A fire in the fireplace
Energy curves…
Kinetic Molecular Theory
Matter is made of molecules.The molecules are in constant motionMolecules move faster, bump into each other
more often if energy is added (aka, if temperature is raised)
This is a theory because it explains what happens with molecules…its not a summary.
Nuclear Fission & Fusion
Fission: the splitting of an atom when it’s bombarded with a small particle, like a neutron. Releases a great amount of energy.
Fusion: the combining of atoms to form heavier ones. Releases more energy than fission. Occurs in the core of stars. Thought to occur after the Big Bang to make the elements in the stars.
Radiation
Ionizing and non-ionizingIonizing: more dangerous. UV rays are
ionizing. Ionizing strips electrons from atoms, causing them to be ionized…these ions are called free radicals and may contribute to human illness like skin cancer.
Non-ionizing: the visible spectrum and the long wavelengths of radiowaves and infrared waves. Produce heat, but does not ionize atoms.
Visible Spectrum
ROYGBIVWavelength
Long = red Short = violet
Frequency Low = red High = Violet
Radiation
Alpha He Least penetrating
Beta Electron Positron
Gamma High energy Accompanied by alpha or beta particles
Nuclear Equations
Thorium-238 undergoes alpha decay. What is the final product?
When Aluminum-26 undergoes electron capture, what is the final product?
Bohr Model
The energy levels are represented as rings around the nucleus. We use it to teach because its easy to understand, but it’s not the accepted model…the Schroedinger model of the atom (the electron cloud model) is the accepted model.
Arrangement of the Periodic Table
MetalsNonmetalsMetalloidsAlkali metalsAlkali earth metalsHalogensNoble GasesPeriodsFamilies
Naming Ionic Compounds
Name the metal, name the non-metal. Add an –ide ending on the nonmetal!
Li2O
CaCl2
Naming Ionic Compounds with a polyatomic Ion
Name the metal, name the poly!
Mg(OH)2
Li3 PO4
Name ionic compounds with a metal that can have more than one charge
1.) determine the charge of the anion2.) the charge of the metal must be equal and
opposite that of the anion.3.) write the charge of the cation as a roman
numeral after the name.SnOMnPPbCl
REDOX
LiCl + K KCl + Li
Li+ + e- LiK K+ + e-
Intermolecular Forces
Dipole-Dipole A dipole is a molecule with a permenant division of charge (+) end of one molecule is attracted to the (-) end of
anotherDispersion
Happens in non-polar molecules Caused by electrons “bunching up” on one side of the
molecule for a moment…making that side of the molecule negatively charged for just an instant
Hydrogen Bond Strongest! Takes the most energy to break. Hydrogen on one molecule is attracted to the lone pair of
electrons on a neighboring molecule.
Intramolecular Bonds / Forces (within the same molecule)
Ionic Electrostatic force Cation & anion Electrons are transferred
Covalent 2 non-metals Electrons are shared
Metallic Electron Sea Swimming valence electrons are attracted to the
positive nucleus on a neighbor Explains properties of metals (malleable, conductors)
Parts of an atom
Nucleus = protons and neutronsElectrons move around the nucleus
Atomic # = # of protonsMass of a proton is about 1 amu
Protons = electrons ( in a neutral atom)Mass # = protons + neutrons
How many protons, neutrons, electrons?
1.) Na p= n= e-=
2.) Na+ p= n= e-=
3.) O p= n= e-=
4.) O-2 p= n= e-=
Heisenberg Uncertainty Principle
the more you know the position of a particle, the less you know about its velocity, and the more you know about the velocity of a particle, the less you know about its instantaneous position.
Half-Life: the amount of time it takes for the mass of a radioactive substance to decrease by 1/2
How long will it take a 20g sample of Carbon-14 to decay to 2.5g?
Stoichiometry
2H2 + O2 2H2O1. If you begin with 1.2x106 moles of hydrogen, how many moles of
water will be produced?
2. If you want to make 3.56g of water, how many moles of oxygen do you need?
3. If you start with .04 moles of hydrogen how many grams of water will you produce?
Metric Conversions
1.) Convert 2.2m to nm:
2.) Convert 1.35x10 34 kilograms to grams:
3.) Change 4.5x1023 milliseconds to hectoseconds:
The Big Bang (see the last page of the study guide)
Explains how hydrogen atoms formedExplains how hydrogen and helium formed
other, heavier elementsExplains the role of the four fundamental
forces in the creation of atoms
Atoms, molecules, ions, isotopes
Atom Basic unit of matter with a dense central nucleus and
electrons that move around the outside. Neutral charge
Molecule Made of atoms bonded together
Ion An atom that has lost or gained electrons and has a charge Cations, anions
Isotope Atoms of the same element that differ in the number of
neutrons Have different atomic masses
Moles and molar mass
1 mole of a compound = the molar mass of the compound, in grams
1 mole of C6H12O6 = 180gHow much does 1 mole of CO2 weigh?
Naming covalent compounds
Name the first element normally If there is only one of the first element, don’t use a prefix Use a prefix if there is more than one of the first element
Name the second element by using a prefix and replacing the ending with –ide.
COCO2
SO3
P5F7
Predicting Products
First you need to know what kind of reaction you’re dealing with:
Combo: A + B ABDecomposition: AB A + BSingle replacement: AB + C CB + ADouble replacement: AB + CD CB + ADCombustion: hydrocarbon + O2 CO2 + H2
O
Predicting Products
Combo: A + B AB Decomposition: AB A + B Single replacement: AB + C CB + A Double replacement: AB + CD CB + AD Combustion: hydrocarbon + O2 CO2 + H2 O
Predict the products of the following reactions:K + AgCl
CH4 + O2
MgO + CaPO4
Balancing Equations
C2H10 + O2 CO2 + H2O
AgCl + Li LiCl + Ag
Na + O2 Na2O
How is different colored light produced when an electric current is passed through a tube full of a
gas?
Electrons in the gas atoms are energized and bump up to higher energy levels. As they fall back to their ground state they emit energy in the form of light. The more energy they lose, the more energetic the light they emit.
Mole conversions
How many atoms of gold are in 629 moles of gold?
How many atoms are in 629 moles of CO2
How many molecules are in 629 moles of CO2
Electron Dot Diagrams
Draw the EDD for an atom of helium:
Draw the EDD for an atom of calcium:
Draw the EDD for NaCl
Draw the EDD for CO2
Stability of isotopes
Macroscopic & Submicroscopic (molecular) views of matter