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Bonding, Compounds, Reactions

Bonding, Compounds, Reactions. Periodic Table Review. What does the periodic table tell me?. Element symbol Atomic number: number of protons (and usually electrons, neutrons) Atomic mass: the average of all the isotopes’ mass What type of element it is (metal, nonmetal, etc)

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Bonding, Compounds, Reactions

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  1. Bonding, Compounds, Reactions

  2. Periodic Table Review

  3. What does the periodic table tell me? • Element symbol • Atomic number: number of protons (and usually electrons, neutrons) • Atomic mass: the average of all the isotopes’ mass • What type of element it is (metal, nonmetal, etc) • What elements can bond together (valence #) • In what ratio elements bond (oxidation #)

  4. Element symbol Atomic mass Atomic number Reading the Periodic Table: Elements S 16 32.06

  5. Types of Elements • Metals: usually shiny, conductors, malleable, ductile, solids at room temperature. On left side of periodic table • Non-metals: gas or brittle solid at room temperature, insulators. On right side of periodic table. • Metalloids: have properties of both metals and non-metals. Between metals and non-metals.

  6. Three types of Elements

  7. Things to remember with symbols • They are either one or two letters. • Only the first letter is capitalized! • Some symbols are based on the Latin name • Some of the newest symbols use three letters until they are renamed (the atomic number in Latin)

  8. Periodic Table Non-metals Noble Gas Metalloids Halogen Metals Transition Metals

  9. Types of Elements • Noble Gas: Chemically stable. Has outer valence level full. “Happy” AKA: Inert elements. Don’t bond with others. • Halogens: Are non-metals. Bond VERY easily. Have 7 electrons in outer shell. • Non-metals: Do not easily conduct electricity or heat. • Metalloids: Have traits of both metals and non-metals. • Metals: Good conductor of heat and electricity, shiny, ductile (pulled into a wire), and malleable (pounded into flat sheets) • Transition metals: Metals that can have two different valence numbers. Is shown in the formula. Example: Fe (II)

  10. Alkali metals Periodic Table Alkaline Earth metals Transition metals

  11. Chemical Bonds • The forces that hold atoms or ions together

  12. Word wizard: Ionic Bond Your definition Important Points Ionic Bond Bond that is formed by the “stealing” of electrons. One atom is now + and one is now -. This makes them attract to each other. Most are solid at room temp. Examples Non-Examples Sodium Chloride: NaCl Sugar: C6H12O6 Water: H2O Diatomic molecules: Cl2, H2, N2 (gasses)

  13. Word wizard: Covalent Bond Your definition Important Points Bond that is formed by the “sharing” of electrons. A stronger bond than ionic. Atoms can share more than one electron. Most are liquid or gas at room temp. Covalent Bond Examples Non-Examples Water: H2O Diatomic molecules: Cl2, H2, N2 (gasses) Sodium Chloride: NaCl Sugar: C6H12O6

  14. Word wizard: Anion Your definition Important Points Anions have more electrons than protons. This makes them negative overall. An ion that has a negative charge; has extra electrons. anion Examples Non-Examples Chlorine Oxygen Nitrogen Non-metals Sodium Potassium Magnesium Metals

  15. Word wizard: Cation Your definition Important Points Cations lose electrons. They have more protons than electrons and are positively charged. An ion that is positively charged; has less electrons Cation Examples Non-Examples Sodium Potassium Magnesium Metals Chlorine Oxygen Nitrogen Non-metals

  16. Word wizard: Chemical Formula Your definition Important Points Large and small letters. Shows what elements are in a compound and how many of each. A shorthand way of writing compounds using their symbols. Chemical formula Examples Non-Examples Water Sugar Salt H2O C6H12O6 NaCl

  17. Word wizard: Chemically Stable Your defintion Important Points Elements that have the outer electron shell full. Also called “Noble Gases” or “Inert Elements” Will not typically bond with other elements. Likes to be ALONE! Chemically Stable Examples Non-Examples Helium Krypton Neon Xenon Argon Radon Gold Carbon Sodium Nickel Potassium Oxygen

  18. Valence Numbers Valence 1 2 3 4 5 6 7 8

  19. Diatomic Molecules • Covalent bond between identical atoms. • Usually a gas • Examples: • H2 (hydrogen gas) • O2(oxygen gas) • N2(nitrogen gas) • Nitrogen has 5 electrons in the outer shell. • It wants 8. • Two nitrogen atoms share three electrons. • BONDED!

  20. Making Compounds Let’s bond, shall we?

  21. Valence Numbers • Valence electrons: how many electrons are in the outer shell. • Chemically stable: elements having their outer shell full. The noble gases are chemically stable without bonding. • To fill the outer shell, elements can share or steal electrons (bond). • To be “Happy” atoms typically want 8 electrons in the outer shell (ionic or covalent bonds)

  22. Ionic bonding • Stealing electrons • This makes one negatively charged (it has an extra electron that it stole). The other is now positively charged (had an electron taken). Opposites attract! • Ionic bonds are weaker than covalent. • Compounds that are solids at room temperature are usually from ionic bonds.

  23. Covalent Bonding • From sharing electrons • Covalent bonds are stronger than ionic • Compounds that are liquids or gas at room temperature are typically covalent bonds. • Diatomic: Some elements will covalently bond with themselves!

  24. Common Household Compounds NaHC03 Baking Soda: Carbon Monoxide: CO SiO2 Sand: Ammonia: NH4 Carbon Dioxide: CO2 Salt: NaCl Bleach: NaClO Propane: C3H8 Vinegar: HCH3O2 Stomach Acid: Water: H2O HCl

  25. Ionic Compound Naming • Metal first then nonmetal • Nonmetal gets –ide ending

  26. Dihydrogen Monoxide • The dangers, uses and potential threats posed by this chemical, Dihydrogen Monoxide, are widespread, and some feel, terrifying. Here is just a small taste of what Dihydrogen Monoxide (DHMO) is: • Some call Dihydrogen Monoxide the "Invisible Killer" • In it’s gaseous form, DHMO can cause severe burns • Dihydrogen Monoxide is found in all cancerous tumors • Athletes use DIHYDROGEN MONOXIDE, or DHMO, to enhance performance • Dihydrogen Monoxide has been found to cause failure in automotive breaks • Dihydrogen Monoxide is a major component of acid rain • Thousands die each year after inhaling dihydrogen monoxide • Dihydrogen Monoxide can be deadly • Visit DHMO.org to find out more

  27. What’s in a name? • Examples: • Carbon Monoxide CO • Carbon Dioxide CO2 • Dihydrogen Monoxide ?? • Mono = one • Di = two • Tri = three • Tetra = four • Penta = five H2O

  28. Covalent Compound Naming • If only one atom in first element the name does not get a prefix • The element farther to the right on the periodic table is named second and ends in -ide

  29. Dot Diagrams • What you need to know to make a dot diagram: • Chemical symbol • valence number • How to draw the dot diagram of an element: 1. Write the symbol 2. Find the valence number 3. Fill in dots • two together (the S ones) • one in other sides until you run out of room. P

  30. More Dot Diagrams F Li Ge Mg Se Kr

  31. I’m still seeing dots! Sr As Why is this one right? He Because Helium only has two electrons in the first place!

  32. Oxidation numbers +1 +3 +/-4 -2 -1 +2 -3

  33. Making Compounds • Criss-Cross Method: • List the Metal first, non-metal second. • Write the oxidation number above the symbol. • Criss-cross the numbers. (a 1 does not need to be written, drop the + or -) • Final answer lists only the subscripts (numbers below the line) • If they are the same number, they cancel out Example: Combine Hydrogen and Chlorine +1 -1 H Cl = HCl

  34. Now try these... Hydrogen and Oxygen +1 -2 H O H2O Magnesium and Nitrogen -3 +2 Mg N Mg3N2

  35. Remember the “criss cross” method. Use the oxidation number Don’t write in 1’s or the charges Oxidation numbers of transition elements are given in a roman numeral. Put in “lowest terms” Writing Equations Example: Combine H and O +1 -2 H O H2O Example: Combine Fe (III) and O +3 -2 Fe O Fe2O3

  36. Monoatomic Ions: “normal” one element can get from the periodic table or roman numerals what you’ve been working with Example: H20 Polyatomic Ions: compounds that always work together. Always has more than one element Get the information off a chart Criss cross method still works. Keep these elements together! Writing Equations: something new Example: Combine Potassium and Permanganate +1 -1 K MnO4 KMnO4

  37. More Practice: Polyatomic Ions Combine: Iron (II) and Nitrate +2 -1 Fe NO3 Fe(NO3)2 Combine: Calcium and Carbonate -2 +2 Ca CO3 CaCO3

  38. Your definition Important Points Alloy Real example Analogy/memory hook Word wizard The mixture can have new properties. (lower melt point, stronger, etc. Two or more metals melted down and mixed together. Not ALL metals are mixtures. (All = alloy) Alloys are like allies (mixed but not the same) Sterling silver, 14 karat gold, bronze, brass

  39. Your definition Basic equation A + B AB Synthesis Reaction Real example Analogy/memory hook 2Mg + O2 2MgO Word wizard Reaction where substances are combined to make a new substance. Like two people going out and becoming a “couple”. Dating is a “sin”

  40. Your definition Basic equation A + BC AC + B D + BC BD + C Single replacement Reaction Real example Analogy/memory hook Li + FeBr2 LiBr + Fe Word wizard One ingredient “kicks out” the other. Leaders always stay leaders! Getting “dumped” for someone else. One ends up single

  41. Your definition Basic equation AB + CD AD + CB Double replacement Reaction Real example AgNO3 + NaCl AgCl + NaNO3 Analogy/memory hook Word wizard Elements will change partners in this type of reaction. Leaders are always leaders! Switching dates at the prom. Nobody gets left alone!

  42. Your definition Basic equation Decomposition Reaction Real example Analogy/memory hook AB A + B 2H2O H2 + O2 elec Word wizard A substance is broken down into its “parts” in this reaction A couple breaking up. Things “break down” when they decompose.

  43. Your definition Basic equation A + B CO2 + H20 Combustion Reaction Real example Analogy/memory hook HCl + Na2CO3 CO2 + NaCl + H2O Word wizard A reaction where two of the products are water and carbon dioxide Combustion = fire Picture a fire with smoke (CO2) and water(H20) to put it out.

  44. Your definition Important Points Endothermic Reaction Real example Analogy/memory hook Word wizard Chemical reaction where heat is ABSORBED. Heat being absorbed makes it feel COLD. Break and shake ice pack. (Heat is absorbed by ice pack, but it feels cold) Endo has a “d” in it. Cold has a “d” in it. Endothermic reactions FEEL cold.

  45. Your definition Important Points Exothermic Reaction Real example Analogy/memory hook Word wizard Chemical reaction where heat is released. This reaction will feel warm/hot. “Exo” = “exit” Heats EXITS an exothermic reaction. (it feels warm) “Hand warmers” BenGay, Thermocare hot wraps

  46. You can’t play “God” • Law of Conservation of Mass says that we can’t create or destroy mass! • Example: the weight of a piece of paper will be the same as the weight of the ash, smoke, etc after you burn it!! • In chemical reactions, you need to have the same amount of atoms before and after the reaction!

  47. Ag + H2S Ag2S + H2 It’s a balancing act Ag 1 Ag 2 H 2 H 2 Not Balanced! Conservation of mass says we can’t create or destroy anything!! S 1 S 1

  48. Ag + H2S Ag2S + H2 It’s a balancing act 2 Ag 1 2 Ag 2 H 2 H 2 S 1 S 1

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