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Some experiments of note:Some experiments of note:
• Greeks view of nature
• J.J. Thompson’s cathode ray
• Ernest Rutherford’s gold foil experiment
• John Dalton’s Atomic Theory
Modern Atomic Theory:Modern Atomic Theory:
1. The Bohr Model of the Atoma) “Planetary” model (K,L,M,N,O,P, and Q or
1-7)
2. The Wave-Mechanical Modela) Electrons move within an orbital
b) An orbital is a region where an electron is most likely to be found.
c) Energy.
Subatomic ParticlesSubatomic Particles
1. Protons and Neutrons -24
a) 1.67 x 10 g = about 1 amu
2. Electrons
a) 1/1800 of an amu
Atomic Mass, Atomic Number, and Atomic Mass, Atomic Number, and Isotopes:Isotopes:
• Atomic mass is the number of neutrons plus the number of protons.
• Atomic number is the number of protons. This can never change for a particular element. What does that mean?
• An Isotope of an element will have different number of neutrons.
More electron stuff:More electron stuff:
• Where are electrons located?
• What are energy levels, and how do electrons move between them?
Ground vs ExcitedGround vs Excited
1. Ground state for sodium:1. Na 2-8-1
2. Excited State for sodium:1. Na 2-7-2
Electon Arrangement:Electon Arrangement:
• The four Quantum Numbers describe the location of an individual electron. Think address!
• No two electrons can have the same four quantum numbers.
Electron ConfigurationElectron Configuration
• According to the Periodic Table
• If you can make a connection with the quantum numbers, electron configuration, and the Periodic Table, then you’ve got it made kid! Let’s try!
Types of MatterTypes of Matter
• Homogeneous – Uniform composition throughout.– Ex/ elements, compounds, and apple juice,.
• Heterogeneous– Different composition throughout.– Ex/ chocolate chip cookie, and rocks in water.
Pure substance vs. MixturesPure substance vs. Mixtures
• Pure substances include elements and compounds. Define them.
• Mixtures can be homogeneous or heterogeneous, are made up of two or more pure substances and can be separated by physical means. What does this mean?
Chemical SymbolsChemical Symbols
• What is a chemical symbol?
• What is it’s purpose?
• Draw the chemical symbol for your favorite element.
Diatomic MoleculesDiatomic Molecules
• Some elements exist in nature as two covalently bonded atoms.
• Make sure you always write with a subscript of 2.
• They are: O2, H2, N2, F2, Cl2, Br2, and I2.
Chemical FormulasChemical Formulas
1. Qualitative information.1. Symbols.
2. Quantitative information.1. Numbers.
More Formulas:More Formulas:
• Empirical Formula• Lowest whole number ratio. Ex/ HO is the
empirical formula for hydrogen peroxide.
• Molecular Formula• Actual chemical formula. Ex/ H2O2 is the molecular
formula for hydrogen peroxide.
Ionic ChargesIonic Charges
• Atoms and compounds are electrically neutral, but ions are not.
• A polyatomic ion is a group of atoms covalently bonded and possessing a charge.
• Many compounds form from oppositely charged ions attracting each other.
Writing Formulas and Naming Writing Formulas and Naming Compounds:Compounds:
• Stoichiometric Coefficients tell us how many there are of a certain molecule or substance. Ex/ 2H2O tells us that there are two molecules of water.
• Equalizing charges allows us to write the chemical formula of a molecule with the appropriate ratio of atoms/molecule. Ex/ Na+ and Cl- combine in a one to one ratio to make NaCl.
Naming CompoundsNaming Compounds
• Binary Ionic compounds:• Positive ion first, negative ion second with “ide”
ending. Ex/ sodium chloride.
• Binary Covalent compounds:• Metal first, then non-metal. Or, if two non-metals,
element with lower electronegativity goes first. Prefixes apply with “ide” ending. Ex/ carbon dioxide.
• The Stock System: • Metals with more than one oxidation state. Ex/
Fe2+ combined with oxygen is Iron (II) oxide.
Chemical Reactions and Equations:Chemical Reactions and Equations:
• Physical Changes-– Often phase changes. No new substance is
formed. Ex/ ice melting.
• Chemical Changes-– Represented by chemical equations.
Reactants and products formed. Ex/ combustion of gasoline. A chemical reaction.
Types of Chemical Rxs Types of Chemical Rxs video:video:
http://www.youtube.com/watch?v=http://www.youtube.com/watch?v=tE4668aarcktE4668aarck
Heat ReactionsHeat Reactions
• Endothermic – Surrounding temperature decreases, PE of
products increases, and ΔH is positive. Ex/H2O(s) + energy → H2O(l)
• Exothermic– Surrounding temperature increases, PE of
products decreases, and ΔH is negative. Ex/Ch4 + 3O2 → CO2 + 2H2O + energy
Balancing Chemical EquationsBalancing Chemical Equations
• The Law of Conservation of Mass:– Says we need equal amounts on both product
and reactant side of a chemical equation.– We can determine an unknown within a
chemical formula based on this law.
• Example: – 2H2(g) + O2 → 2H2O(g)
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