1. “Whether you think you can, or you think you can’t - you’re right.” - Henry Ford

2. Review of Chapter 1: The Atom

3. History of Atomic Theories

4. Parts of an Atom  Nucleus  Protons: positive charge, mass = 1 amu  Neutrons: no charge, mass = 1 amu  Electrons  Negative charge, mass = 0 amu  Valence e- are the outermost ones  Located somewhere in orbitals, regions of e- density  amu is an “atomic mass unit”, a unit of weight

5.  Remember: # protons = # electrons in uncharged atoms

6. Atomic Number  Atomic number is # of protons (and # of electrons)  Mass number is # of protons and neutrons combined, gives “weight” of atom

7. Isotopes  Isotopes are different versions of the same element  Same atomic number (# protons)  Different mass number (from different # neutrons)  H-1  H-2  H-3

8. Calculating Atomic Mass (amu-1)(%1) + (amu2)(%2) + (amu3)(%3) + …

9. Electron Locations  Electrons are in orbitals  Ground state is the lowest level  Electrons can absorb energy and move to a higher level, or excited state  Release energy as they drop back down

11. Review of Chapter 2: Formulas and Equations

12. Formula Basics  Symbols identify elements: K, Na, O, F, Mg, Sb  Formulas give info from symbols and numbers NaCl NH 3 CH 3 Br  Qualitative info can’t be counted (quality).  Ex: what elements are present  Quantitative info can be counted (quantity).  Ex: how much of each element?

13. Writing Formulas  Coefficients are written in front of a formula, tells how many of the formula there are 3 CO 2 5 H 2 O 8 NH 3  Subscripts are small, after symbols, and tell how many atoms there are of each element 3 CO 2 5 H 2 O 8 NH 3

14. Ions  Uncharged atoms have same # of protons and electrons  Ions are atoms that lose or gain electrons, become charged: Cl-, Na+, Cu  Polyatomic ions are charged molecules: NH 4 +, SO 4, NO 3 - 2+ 2-

15. Equalizing Charges

16. Naming Compounds  Ionic (M/NM) compounds: use name of (+) element (metal), change end of (-) nonmetal to “-ide.” Ex: NaCl = Sodium chloride  Polyatomic ions keep their names  Covalent (NM/NM) compounds: less electronegative atom written first, each is named with “mono-, di-, tri-, tetra-” prefixes.  Ex: N 2 O 4 = Dinitrogen tetroxide

17. Roman Numerals in Names  Use a numeral in names when an atom has several options of what its charge can be  Copper (III) sulfate means the copper atom has a +3 charge, as opposed to other possible charges. Cu 2 (SO4) 3  Lead (II) nitrate = Pb(NO 3 ) 2

18. Ch-ch-ch-changes  Physical changes affect form of starting material, but stays same substance  Cheese melting, chopping wood  Chemical changes produce new substances  Burning wood, mixing acid & base

19. Chemical Reaction Equations  Reactant + Reactant  Product + Product HCl + NaOH  H 2 O + NaCl  Law of Conservation of Mass says whatever’s on the left needs to be on the right, nothing created or destroyed

20. 4 Types of Reactions  Addition: A + B  C  Things come together  Decomposition: C  A + B  Something breaks apart  Single Replacement: AB + C  A + BC  Part of a compound is replaced  Double Replacement: AB + CD  AD + BC  All the pieces of a compound switch around