2. 1 - 1 © Chemeketa Community College: CH117 CH117 Chemistry in the Kitchen Unit 2 Chemistry Basics Periodic Table Ionic and Covalent Compounds Utensils in Cooking Functional Groups in Flavor Molecules

3. 1 - 2 © Chemeketa Community College: CH117 stuff The stuff things are made of. Mass Volume Has Mass and Volume (takes up space). (Air, water, rocks, etc..) Matter What is Chemistry? Mass amount Mass = The amount of stuff (in g’s) ( Bowling Ball > Balloon) Weight Weight = Pull of Gravity on matter. “The study of Matter and its Changes.”

4. 1 - 3 © Chemeketa Community College: CH117 Pure Substance Pure Substance - something of uniform composition that can’t be sorted further by differences. A model of matter ie. Table of known elements Element Element - Pure substance composed of only one kind of atom. Chemical Compound Chemical Compound - A pure substance that is a combination of different elements. ie. Carbon Dioxide (CO 2 ) ie. Water (H 2 O) ie. Salt (NaCl)

5. 1 - 4 © Chemeketa Community College: CH117 Mixture Mixture - NOT of uniform composition and CAN be sorted further by differences. A model of matter ie. Homogenized Milk Homogeneous Homogeneous – Looks pure but is not. Heterogeneous Heterogeneous - Visibly a combination of different substances. ie. Chocolate Chip Cookies ie. Salt or Sugar Water (H 2 O + NaCl) ie. Pizza ie. Granite

6. 1 - 5 © Chemeketa Community College: CH117 Classification of matter Matter Pure Substance MixtureElementCompound Fe FeS MgMgO Mg + O 2 Fe + S Homogeneous Heterogeneous

7. 1 - 6 © Chemeketa Community College: CH117 Pizza Mixture Homogeneous (Solution) (Solution)Heterogeneous Mixtures Non-uniform compositionNon-uniform compositionNon-uniform compositionNon-uniform composition Uniform composition Air Urine Gasoline Sand Tea w/ice Milk

8. 1 - 7 © Chemeketa Community College: CH117 Each element is assigned a unique symbol 1-2 letters; 1st is capitalized Elements & Symbols Hydrogen Nitrogen Aluminum Chlorine Calcium Carbon Copper (Cu) The original name is often of Latin or Greek origin Potassium (Kalium) Sodium (Natrium) Iron (Ferrum) Gold (Aurum)

9. 1 - 8 © Chemeketa Community College: CH117 Modern periodic table H Li Na Cs Rb K TlHgAuHfLsBa Fr PtIrOsReWTa He RnAtPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNiCoFeMnCrV InXeITeSbSn GaKrBrSeAsGe AlArClSPSi BNeFONC I A II A III A IV A V A VI A VIIA VIIIA III B IVB V B VIB VIIB VIII B IB IIB 12345671234567 Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es The periodic table helps us understand behavior,behavior, reactionsreactions propertiesproperties of the elements. Mendeleev, 1871 “Properties of the elements vary in a periodic manner.”

10. 1 - 9 © Chemeketa Community College: CH117 A row or period He Rn XeI KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLsBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNiCoFeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es At Te As Si B 12345671234567 Periods are assigned numbers Periods are assigned numbers

11. 1 - 10 © Chemeketa Community College: CH117 Common group names H Li Na Cs Rb K TlHgAuHfLaBa Fr PtIrOsReWTa He RnAtPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNiCoFeMnCrV InXeITeSbSn GaKrBrSeAsGe AlArClSPSi BNeFONC I A III B IVB V B VIB VIIB VIII B IB IIB Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es Alkali Metals Alkaline Earth Metals HalogensHalogens Noble gases III A IV A V A VI A VIIA VIIIA II A Transition Metals LanthanidesLanthanides ActinidesActinides

12. 1 - 11 © Chemeketa Community College: CH117 Why do we have those rows on the bottom? H Li Na Cs Rb K LsBa Fr Be Mg Sr Ca Y AcRa Sc TlHgAuHfPtIrOsReWTa He RnAtPoBiPb CdAgZrPdRhRuTcMoNb ZnCuTiNiCoFeMnCrV InXeITeSbSn GaKrBrSeAsGe AlArClSPSi BNeFONC Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es This arrangement takes too much space and is hard to read.

13. 1 - 12 © Chemeketa Community College: CH117 Names & Symbols He Rn XeI KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLsBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNiCoFeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es At Te As Si B 12345671234567 Know the names & symbols Know the names & symbols

14. 1 - 13 © Chemeketa Community College: CH117 At Te As Si B He Rn Xe I KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLsBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNi Co FeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es MetalsMetals Lustrous, malleable and ductile. Solids at room temp (except Hg) Conductors (heat & electricity); electrons loose so can move freely (flow) and spread energy so make good cooking pans (ie. Al, Fe, Cu) Give electrons away to nonmetals (Form (+) ions ). Lustrous, malleable and ductile. Solids at room temp (except Hg) Conductors (heat & electricity); electrons loose so can move freely (flow) and spread energy so make good cooking pans (ie. Al, Fe, Cu) Give electrons away to nonmetals (Form (+) ions ).

15. 1 - 14 © Chemeketa Community College: CH117 High SpHt; Resists change Remember Specific Heat Fe0.11 Cu 0.093 Ag 0.057 Au 0.031 Sand 0.19 Al 0.22 H 2 O 1.00 1o1o 10 o 30 o 20 o Low SpHt; Heats quickly Cast Iron skillets (Fe/C) have more mass compared to normal Al or Stainless steel pans which is why they heat & cool slowly and hold heat longer than an Al or Fe pan of lower mass. Stainless steel (Fe/Cr/Ni all ~0.1) heats fast. Cu on bottom heats faster.

16. 1 - 15 © Chemeketa Community College: CH117 He Rn XeI KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLsBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNiCoFeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es At Te As Si B Non-metalsNon-metals Gasliquidsolid (dull, brittle); Gas, liquid, solid (dull, brittle); Many are diatomic Poor conductors (Insulators); electrons held rigid in covalent bonds so can’t flow. Glass, SiO 2, heats slower than metal; Baking (hot air) is slower than Frying or boiling. Convection ovens make faster. Take electrons from metals (Form (-) ions); Share electrons (covalent) with other non-metals Gasliquidsolid (dull, brittle); Gas, liquid, solid (dull, brittle); Many are diatomic Poor conductors (Insulators); electrons held rigid in covalent bonds so can’t flow. Glass, SiO 2, heats slower than metal; Baking (hot air) is slower than Frying or boiling. Convection ovens make faster. Take electrons from metals (Form (-) ions); Share electrons (covalent) with other non-metals

17. 1 - 16 © Chemeketa Community College: CH117 He Rn Xe I KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLsBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNiCoFeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es At Te As Si B 3 - 11 MetaloidsMetaloids Intermediate properties Semi conductors Intermediate properties Semi conductors

18. 1 - 17 © Chemeketa Community College: CH117 H Li Na Cs Rb K TlHgAuHfLsBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNi Co FeMnCrV InSn Ga Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es He Rn XeI KrBrSe ArClS NeFO P NC Sb Ge At Te As Si B MetaloidsMetaloids MetalsMetals Non-metalsNon-metals

19. 1 - 18 © Chemeketa Community College: CH117 A model of matter ie. Aluminum (Al) Atom Atom - The smallest unit of an element that is still that element. ie. Carbon Dioxide (CO 2 ) ie. Water (H 2 O) Molecule Molecule -The smallest unit of bonded atoms that is still that substance. Contains > 1 atom or element Contains > 1 atom or element. ie. Oxygen (O 2 ) ie. Not Salt (NaCl)

20. 1 - 19 © Chemeketa Community College: CH117 Structure of the atom Nucleus + Small, dense, + charge in the center of an atom. containsprotons & neutrons + + + + ++

21. 1 - 20 © Chemeketa Community College: CH117 Structure of the atom Nucleus (+) Electrons - - charged particles that surround the nucleus. Electrons nucleusorbitals Electrons move around nucleus in orbitals.

22. 1 - 21 © Chemeketa Community College: CH117 Structure of the atom nucleus The nucleus is a small part of an atom. If the nucleus was the size of a marble, the atom would fill a football stadium. The nucleus would weigh over 10,000 tons.  Atoms are mostly empty space.  Atoms have a small, dense nucleus with + charge.

23. 1 - 22 © Chemeketa Community College: CH117 A A = Atomic mass The atomic symbol X A Z C # C C = Charge = + or - values # # = Number of atoms in a formula. Z = Atomic number = # protons = # electrons

24. 1 - 23 © Chemeketa Community College: CH117 A A = Atomic mass The atomic symbol O 16 8 2- C C = Charge = + or - values # # = Number of atoms in a formula. Z = Atomic number = # protons = # electrons

25. 1 - 24 © Chemeketa Community College: CH117 Electron arrangement 2 8 18 32 Electrons fill layers around nucleus Low  High Shells = Energy levels 2412 Mg A new layer is added for each row or period in the table.

26. 1 - 25 © Chemeketa Community College: CH11711H 73Li 42He IA II A 94Be 2, 1 2, 2

27. 1 - 26 © Chemeketa Community College: CH117115B 11H 73Li IA II A IIIA 94Be 2, 1 2, 2 2, 3

28. 1 - 27 © Chemeketa Community College: CH117115B 126C 137N IIIA IVA VA 2, 3 2, 4 2, 5

29. 1 - 28 © Chemeketa Community College: CH11794Be 11H 73Li 42He 2010Ne 2311 Na 2412 Mg 4018 Ar IA IIA VIIIA 2, 1 2, 2 2, 8, 1 2, 8, 2 2, 8 2, 8, 8

30. 1 - 29 © Chemeketa Community College: CH11711H 73Li 42He 94Be 2010Ne 2311 Na 2412 Mg 4018 Ar 881122 2, 1 2, 2 2, 8 2, 8, 1 2, 8, 2 2, 8, 8 Octet Rule

31. 1 - 30 © Chemeketa Community College: CH117 33 2412 Mg 11H 73Li 2311 Na 94Be 115B 2713 Al Valence electrons Where most chemical Reactions occur. 11 22 2, 1 2, 2 2, 8, 1 2, 8, 2 2, 3 2, 8, 3

32. 1 - 31 © Chemeketa Community College: CH11711H 73Li 2311 Na Electron Dot Structures Show only Valence Electrons H Li Na K

33. 1 - 32 © Chemeketa Community College: CH117 H Li Na K He Be B C O F Ne N Mg Ca Al Ga Si Ge P As S Se ClBrArKr 1 234567 8 Electron Dot Structures

34. 1 - 33 © Chemeketa Community College: CH117 Electron Affinity At I Br Cl Po Te Se S Bi Sb As P Pb Sn Ge Si FON Tl Na Cs Rb K Ba Mg Sr Ca In Ga Al H LiBeBC 4 - 50 Relative ability of atoms to attract electrons Oxidation : When electrons are grabbed by a “hungry” element like Oxygen (O) or Chlorine (Cl) Metals hold e - s loosely and easily give them away Nonmetals hold e - s tight and easily take them or share

35. 1 - 34 © Chemeketa Community College: CH117 2311 Na Ions Metals give e - s to make (+) ions ( Cations) Na 11 +’s 11 -’s 0 11 +’s 11 -’s 0 11 +’s 10 -’s 1 + 1 + 11 +’s 10 -’s 1 + 1 + Na 1+ 2, 8 = [Ne] Now has e - s like Ne 2, 8 = [Ne] Now has e - s like Ne

36. 1 - 35 © Chemeketa Community College: CH117 Ions Nonmetals take e - s to make (–) ions (anions) 17 +’s 17 -’s 0 17 +’s 17 -’s 0 17 +’s 18 -’s 1 - 1 - 17 +’s 18 -’s 1 - 1 - Cl 1- 3517 Cl = Cl 1- 2, 8, 8 = [Ar]

37. 1 - 36 © Chemeketa Community College: CH117 Formation of NaCl Na + Cl Na + + Cl + and - ions attract to form an ionic bond. _ e- moves from Metal  Nonmetal Metal Cation Nonmetal Anion Stable octets Chemical Equation = expression of a reaction Na + Cl  NaCl Salts are ionic.

38. 1 - 37 © Chemeketa Community College: CH117 Common ions H Li Na Cs Rb K TlBa Fr He RnAtPoBiPb Be Mg Sr Ca Ra InXeITeSbSn GaKrBrSeAsGe AlArClSPSi BNeFONC HgAuHfLsPtIrOsReWTa CdAgZrYPdRhRuTcMoNb Ac ZnCuTiScNiCoFeMnCrV Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es 1+ 2+2+3+3+ 4+4-4+4- 3-3-2-2-1-1- Transition Elements VariableVariable Representative Elements

39. 1 - 38 © Chemeketa Community College: CH117 Ionic Formulas Metal Cations + Nonmetal Anions Na 1+ Cl 1- NaCl Sodium Chloride Mg 2+ Cl 1- MgCl 2 Magnesium Chloride Cl 1- In Sea Salt; tastes bitter Table Salt Used for taste & preserving Mined from earth & from Sea

40. 1 - 39 © Chemeketa Community College: CH117 Polyatomic Ions Ca 2+ CO 3 2- CaCO 3 Calcium Carbonate Mg 2+ SO 4 2- MgSO 4 Magnesium Sulphate Sea shells, egg shells, Limestone, Marble; Used to remove Ca from sea salt In Sea Salt

41. 1 - 40 © Chemeketa Community College: CH117 Examples of Ionic Compounds Potassium Iodide (to iodize salt) CuO TiO 2 CaCO 3 Fe 2 SO 4 NaHCO 3 Ca 3 (PO 4 ) 2 KNO 3 KI Copper (II) Oxide or Cupric Oxide Titanium oxide (white paint pigment) Calcium Carbonate (egg shells) Potassium Nitrate (in fertilizer) Ferric Sulfate (Iron in vitamins) Sodium bicarbonate (baking soda) Calcium Phosphate (in milk) Common ingredients

42. 1 - 41 © Chemeketa Community College: CH117 H Li Na K He Be B C O F Ne N Mg Ca Al Ga Si Ge P As S Se ClBrArKr 1 234567 8 Metals give e-s to nonmetals Nonmetals Share e-s with other nonmetals Nonmetals Share e-s with other nonmetals

43. 1 - 42 © Chemeketa Community College: CH117 Covalent Bonds H H + HHClO + O + + N N N NO O H 2 H-H H 2 Cl 2 Cl-Cl Cl 2 O 2 O=O O 2 N 2 N N N 2

44. 1 - 43 © Chemeketa Community College: CH117 OC OC Covalent Bonds O=C=O C O O Carbon monoxide Carbon dioxide CO 2 May modify rules to improve sound. iemonmono ie - monoxide not monooxide.

45. 1 - 44 © Chemeketa Community College: CH117 CO CO 2 SiO 2 CH 4 CH 3 CH 2 CH 3 CH 3 CH 2 OH CH 3 CO 2 H C 12 H 22 O 11 Examples of Covalent compounds Methane (Natural gas) carbon monoxide carbon dioxide silicon dioxide (in sand, glass) Propane (cooking gas) Ethanol (drinking alcohol) Acetic Acid (vinegar) Sucrose (table sugar)

46. 1 - 45 © Chemeketa Community College: CH117 Properties of Ionic “Salts” Not individual molecules Form crystal arrays where Ions touch many others Formula represents the average ion ratio NaCl sodium chloride NaCl sodium chloride Melting points very high (NaCl mp = 801 o C) Ions come apart if dissolved in water. Act as electrolytes.

47. 1 - 46 © Chemeketa Community College: CH117 Covalent compounds Discrete molecular units Atoms held together by bonds Covalent compounds exist in all states (CO 2 - gas, H 2 O - liquid, SiO 2 - solid) Formula represents atoms in a molecule Properties of covalent compounds O=O

48. 1 - 47 © Chemeketa Community College: CH117 Bond Polarity Cl H Electrons in covalent bonds rarely get shared equally. polar This unequal sharing results in polar covalent bonds. H Cl Slight positive Smaller pull Slight positive Smaller pull Slight negative Larger pull Slight negative Larger pull ++ -- HH O ++++ ++++ ----

49. 1 - 48 © Chemeketa Community College: CH117 HH O ++++ ++++ ---- HH O ++++ ++++ ---- HH O ++++ ++++ ---- HH O ++++ ++++ ---- Polar Attraction Attractive Forces Hydrogen Bonds

50. 1 - 49 © Chemeketa Community College: CH117 Ionic vs Covalent Strong attractions: Ionic High mp (1474F,801C) High bp (2575F, 1413C) Moderate attractions: Polar; H-bonds Low mp H 2 O (0C), Low bp H 2 O 100C; EtOH 78C Weak attractions: Vander Waals Lowest mp/bp Ionic Polar Covalent Nonpolar covalent Like NaClLike sugar, water, ethanol, Vit C Like oil, gasoline, hexane, Vit C

51. 1 - 50 © Chemeketa Community College: CH117 ClCl ++++ ---- Cl ++++ ---- Cl Attractive Forces Van der Waals (Dispersion Forces) 0.01 kcal mol 0.01 kcal mol Melting Point Cl 2 -102 o C CH 4 -183 o C Melting Point Cl 2 -102 o C CH 4 -183 o C Cl ++++ ----Cl Cl ++++ ---- Cl

52. 1 - 51 © Chemeketa Community College: CH117 Hydrogen Bonding of Water Hydrogen Bonds 5 - 10 kcal mol 5 - 10 kcal mol Melting Point H 2 O 0 o C NH 3 -78 o C Melting Point H 2 O 0 o C NH 3 -78 o C Boiling Point H 2 O100 o C NH 3 -33 o C Boiling Point H 2 O100 o C NH 3 -33 o C

53. 1 - 52 © Chemeketa Community College: CH117 Ionic vs Covalent Strong attractions: Ionic High mp (1474F,801C) High bp (2575F, 1413C) Moderate attractions: Polar; H-bonds Low mp H 2 O (0C), Low bp H 2 O 100C; EtOH 78C Weak attractions: Vander Waals Lowest mp/bp Many water solubleSoluble in waterInsoluble in water Form ions in water (electrolytes) Don’t ionize in water Ionic Polar Covalent Nonpolar covalent Like NaClLike sugar, water, ethanol, Vit C Like oil, gasoline, hexane, Vit C

54. 1 - 53 © Chemeketa Community College: CH117 Dissoving of Ionic Compounds “Like Dissolves Like” Polar water attracts to Na + and Cl - ions Polar water attracts to Na + and Cl - ions When an ionic solid dissolves in water, the polar solvent removes ions from the crystal lattice.

55. 1 - 54 © Chemeketa Community College: CH117 H H O - + H H O - + H - H O + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + “Like Dissolves Like” Dissoving of Ionic Compounds

56. 1 - 55 © Chemeketa Community College: CH117 Dissolving of covalent compounds Covalent compounds do not break into ions. H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - + H H O - +

57. 1 - 56 © Chemeketa Community College: CH117 Electrolytes Na + NaCl Na + Cl - C 6 H 12 O 6 Ionic (Salt) Covalent (sugar) Dissolved Ions in solution No Ions in solution NaCl  Na + + Cl -

58. 1 - 57 © Chemeketa Community College: CH117 Ionic vs Covalent Ionic Polar Covalent Nonpolar covalent Like NaClLike sugar, water, ethanol, Vit C Like oil, gasoline, hexane, Vit C Strong attractions: Ionic High mp (1474F,801C) High bp (2575F, 1413C) Moderate attractions: Polar; H-bonds Low mp H 2 O (0C), Low bp H 2 O 100C; EtOH 78C Weak attractions: Vander Waals Lowest mp/bp Many water solubleSoluble in waterInsoluble in water Form ions in water (electrolytes) Don’t ionize in water Not flammableFlammable

59. 1 - 58 © Chemeketa Community College: CH117 Organic Functional Groups Hydrocarbons

60. 1 - 59 © Chemeketa Community College: CH117 Drawing Covalent Compounds Practice building: Build with models Hexane Ethylene Ethanol (an alcohol) Isopropyl alcohol Cinnamaldehyde (an aldehyde) Acetone (a ketone) Acetic Acid (a carboxylic acid) Butyric Acid Phenol

61. 1 - 60 © Chemeketa Community College: CH117 Flavors: Terpenes Limonene Orange/lemons Citronellol Roses/geraniums

62. 1 - 61 © Chemeketa Community College: CH117 61 Smell: S-(+)-carvone Caraway (Dill) (Manderine Orange Peel) Caraway (Dill) (Manderine Orange Peel) R-(-)-carvone Spearmint

63. 1 - 62 © Chemeketa Community College: CH117 Flavors: Phenols Compounds of phenol are the active ingredients in the essential oils of cloves, vanilla, nutmeg, and mint. Nutmeg Thyme Cloves Vanilla Rosemary

64. 1 - 63 © Chemeketa Community College: CH117 Pungent Flavors Allyl isothiocyanate Thiocyanates: in Mustards and Horseradish Alkylamides: in chilli’s, & pepper CapsaicinPiperine GingerolShogoal

65. 1 - 64 © Chemeketa Community College: CH117 Tetrahedral electron-pair Geometries Tetrahedral Pyramidal Bent