Transcript Slide 1
• Significant Figures – start at the left and proceed to the right 1. If the number does not have a decimal point count until there are no more non zero numbers 2. If the number has a decimal point start counting at the first non-zero number and continue counting until you run out of decimal places • Vocabulary 1. Observation 17. Law of Conservation of Mass 33. percent weight 2. Hypothesis 18. Law of Conservation of Energy 34. percent error 3. Experiment 19. Exact numbers 35. percent composition 4. Theory 20. Accuracy 36. percent yield 5. Law 21. Precision 37. %RSD 6. Chemistry 22. compounds 38. limiting reactant 7. Matter 23. molecules 39. Stoichiometry 8. Energy 24. chemical formula 40. Stoichiometric Coefficient 9. Chemical Properties 25. empirical formula 41. Electron Affinity 10. Physical Properties 26. molecular formula 42. Electronegativity 11. Extensive Properties 27. structural formula 43. Covalent Bond 12. Intensive Properties 28. bond line formula 44. Ionic Bond 13. Scientific (natural) law 29. ball and stick model 45. Dipole 14. Anion 30. space filling model 46. London Dispersion Forces 15. Cation 31. mole 47. Resonance 16. Molecular Geometry 32. Electronic Geometry 48. Hybrid orbital 49. area of high electron density Table of Common Ions Common Positive Ions (Cations) Monovalent Hydronium (or hydrogen) Lithium Sodium Potassium Rubidium Cesium Francium Silver Ammonium Thalium Copper I H3O+ H+ Li+ Na+ K+ Rb+ Cs+ Fr+ Ag+ NH4+ Tl+ Cu+ Divalent Magnesium Calcium Strontium Beryllium Manganese II Barium Zinc Cadmium Nickel II Palladium II Platinum II Copper II Mercury II Mercury I Iron II Cobalt II Chromium II Lead II Tin II Mg2+ Ca2+ Sr2+ Be2+ Mn2+ Ba2+ Zn2+ Cd2+ Ni2+ Pd2+ Pt2+ Cu2+ Hg2+ Hg22+ Fe2+ Co2+ Cr2+ Pb2+ Sn2+ Trivalent Aluminium Antimony III Bismuth III Al3+ Sb3+ Bi3+ Iron III Cobalt III Chromium III Fe3+ Co3+ Cr3+ Table of Common Ions Common Negative Ions (Anions) Monovalent Hydride Fluoride Chloride Bromide Iodide Hydroxide Permangante Cyanide Thiocynate Acetate Nitrate Bisulfite Bisulfate Bicarbonate Dihydrogen phosphate Nitrite Amide Hypochlorite Chlorite Chlorate Perchlorate HFlClBrIOHMnO4CNSCNC 2H 3O 2NO3HSO3HSO4HCO3H2PO4NO2NH2ClOClO2ClO3ClO4- Divalent Oxide Peroxide Sulfide Selenide Oxalate Chromate Dichromate Tungstate Molybdate tetrathionate Thiosulfate Sulfite Sulfate Carbonate Hydrogen phosphate Trivalent Nitride O2O22S2Se2C2O42CrO42Cr2O72WO42MoO42S4O62S2O32SO32SO42CO32HPO42- Phosphate N3- PO43- Given or determined from balanced stoichiometric equation mass of molecule Molar Mass given or calculated from periodic table density molarity, ppm, molality, normality, etc. Vol solution Concentration solution Calculate from molecular formula or balanced equation moles of molecule Avogadro's Number Molar Ratio moles of element, or other reactant or product Number of molecules These concepts lead to solving problems determining limiting reactant and percent yield. Molar Mass given or calculated from periodic table Avogadro's Number Mass of element, or reactant or product Number of atoms, or molecules of reactant or product Quantum Numbers n and l define the energy of the electron The principal quantum number has the symbol ~ n which defines the energy of the shell n = 1, 2, 3, 4, ...... “shells” The angular momentum quantum number has the symbol ~ which defines the subshells. = 0, 1, 2, 3, 4, 5, .......(n-1) = s, p, d, f, g, h, .......(n-1) The symbol for the magnetic quantum number is m which defines the orbital. m = - , (- + 1), (- +2), .....0, ......., ( -2), ( -1), The last quantum number is the spin quantum number which has the symbol m s which characterizes the single electron. The spin quantum number only has two possible values. ms = +½ or -½ one spin up ↑ and one spin down ↓ Electrons: The Nucleus: Hund’s Rule states that each orbital will be filled singly Build by adding the required number of protons before pairing begins. The singly filled orbitals will have (the atomic number) and neutrons (the mass of the atom) a parallel spin. Pauli’s Exclusion Principle states that paired electrons in an orbital will have opposite spins. Fill the electrons in starting with the lowest energy level adhering to Hund’s and Pauli’s rules. Ionic Polar Covalent Covalent Determine Inductive effect Count the number of electrons the element should have Determine how equally electrons are shared (DEN) >1.7 consider it ionic Oxidation number Never Have a Full Octet Formal charge Always Have a Full Octet Sometimes Have a Full Octet Sometimes Exceed a Full Octet To calculate a formal charge 1. draw the Lewis dot structure 2. draw circles around each atom and the electrons associated with it. Remember that formal charges are associated with covalent bonds and that all electrons are shared equally. 3. compare to the group number for that atom. If the number is larger the formal charge is negative, smaller the formal charge is positive. To calculate an oxidation number 1. list all the elements follow with an equal sign 2. follow with the number of atoms of that type in the molecule 1. follow with a multiplication sign 2. If the element is O follow with a -2 3. If the element is H follow with a +1 4. any other element enter a ? 5. follow with an = sign, do the math 6. draw a total line, then enter the charge on the molecule 7. Do the algebra backwards to solve for ? VSEPR Theory Lone pair to lone pair is the strongest repulsion. 2 Lone pair to bonding pair is intermediate repulsion. 3 Bonding pair to bonding pair is weakest repulsion. • Mnemonic for repulsion strengths lp/lp > lp/bp > bp/bp • Lone pair to lone pair repulsion is why bond angles in water are less than 109.5o. Electronic geometry is determined by the locations of regions of high electron density around the central atom(s). Electron pairs are not used in the molecular geometry determination just the positions of the atoms in the molecule are used. Molecular geometry determined by the arrangement of atoms around the central atom(s). Summary of Electronic & Molecular Geometries Regions of High Electron Density Electronic Geometry Hybridization 2 Linear sp 3 Trigonal planar sp2 4 Tetrahedral sp3 5 Trigonal bipyramidal sp3d 6 Octahedral sp3d2