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Today is Friday (!), March 14 th , 2014

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  1. In This Lesson: Unit 3 Ionic Nomenclature and Polyatomic Ions (Lesson 1 of 4) • Stuff You Need: • Periodic Table • Paper Towel Today is Friday (!),March 14th, 2014 Pre-Class: Can you name these compounds? H2O CO2 NaCl HCl Today you will need your periodic tables that show the charges for transition metals. You also need a small paper towel for you and your partner.

  2. Pre-Class Deux • Can you name these compounds? • O2 • Oxygen gas • O3 • Ozone gas • CO • Carbon monoxide • H2SO4 • Sulfuric Acid

  3. Today’s Agenda • Namin’ stuff. • In today’s case, ionic compounds and polyatomic ions. • Where is this in my book? • P. 254 and following…

  4. By the end of this lesson… • You should be able to name binary ionic compounds that include polyatomic ions.

  5. Quick Reminders • A compound is a chemical combination of two or more elements (like the pre-class ones). • Subscripts indicate how many atoms of an element are present. • H2O = 2 Hydrogen, 1 Oxygen • CO2 = 1 Carbon, 2 Oxygen • Note that subscripts only apply to the letter next to them (unless there are parentheses).

  6. Quick Reminders • Chemists don’t write ones. • Na+ has a charge of 1+. • Cl- has a charge of 1-. • K2S has onesulfur atom.

  7. Quick Reminders Charge (1-) Nd2 - Subscript (2 Nd atoms)

  8. Quick Reminders • For elements whose symbols have two letters (or even three), only the first letter is capitalized. • For example, Cesium is abbreviated Cs. • If you write CS, another person might think it’s a compound of Carbon (C) and Sulfur (S).

  9. Quick Reminders • Remember that cations are positively-charged ions, and anions are negatively-charged. • Most cations are metals; some polyatomic ions. • Example: Ca2+, NH4+ • Most anions are nonmetals; many polyatomic ions. • Example: Cl-, SO42-

  10. Cations and Anions • And since cations and anions attract one another… • They form ionic bonds, making ionic compounds.

  11. Need to Know Information • Now, to name any compound or derive its formula, you need to know: • What kind of elements are involved? • Metal, nonmetal, or metalloid. • How many elements are there? • 2 – binary compound • 3 – ternary compound (usually has a polyatomic ion) • What kind of charge does it create? • Positive, negative, or neutral. • Are there polyatomic ions?

  12. Wait…polyatomic? • Polyatomic ions are (usually) small compounds that behave as one ion. • In other words, there’s more than one element, but they act as one. Poly-atomic…get it? • You should memorize as many of these as possible. • Yes, really. • Here’s a hint: • Anything ending in “-ide,” except Hydroxide, Peroxide, and Cyanide, will be found on the periodic table. • Everything else is on the polyatomic ion charts.

  13. Polyatomic Ion List • I will give you a list of polyatomic ions, but I assure you that studying/memorizing the list will be extremely helpful. • Note: You will not have a polyatomic ion list on the final. • Also helpful will be the following slide that shows how many of the names for polyatomic ions are determined. • Important Note: • “Hydrogen carbonate” is the same as “Bicarbonate.” • “Hydrogen sulfite” is the same as “Bisulfite.” • “Hydrogen sulfate” is the same as “Bisulfate.” • Acetate is more commonly written as C2H3O2-

  14. Naming Polyatomic Ions

  15. Naming Polyatomic Ions with Chlorine

  16. Naming Polyatomic Ions

  17. Most Common Polyatomic IonsThese are worth memorizin’! • Acetate(C2H3O2-) • Carbonate(CO32-) • Chlorate(ClO3-) • Hydroxide(OH-) • Nitrate(NO3-) • Phosphate (PO43-) • Sulfate (SO42-) • Ammonium (NH4+)

  18. Time for some practice! • Polyatomic Ion Puzzle • The puzzle is like dominoes - match the names of polyatomic ions to their formulas. • Note that some sides may not be used. • Some ions are represented more than once. • Try many possibilities – don’t give up! • HINTS: • There are four obvious corner pieces. • Cyanide, chromate, dichromate, hydrogen carbonate, and permanganate only have one match each. • It’s a 4x4 grid.

  19. Now that that’s over… • Let’s make sure we know how to predict ionic charges a little more specifically.

  20. Group 1 H+ Group 1: Lose 1 electron to form 1+ ions Li+ Na+ K+

  21. Group 2 Be2+ Mg2+ Group 2: Lose 2 electrons to form 2+ ions Ca2+ Sr2+ Ba2+

  22. Group 13 Group 13: Ga3+ Group 13: Lose 3 electrons to form 3+ ions Al3+ B3+

  23. Group 14 Group 14: Group 14:Rarely form ions

  24. Group 14 Group 14: Ge4+ Group 14:4+ or 2+ ions Sn4+ Pb2+

  25. Group 15 Nitride Group 15: Gain 3 electrons to form 3- ions N3- P3- Phosphide As3- Arsenide

  26. Group 16 Group 16: O2- Oxide Group 16: Gain 2 electrons to form 2- ions S2- Sulfide Se2- Selenide

  27. Group 17 Group 17: I- Iodide Group 17: Gain 1 electron to form 1- ions Br- Bromide F- Fluoride Cl- Chloride

  28. Group 18 Group 18: Group 18: Noble gases do not form ions

  29. Hey, wait a sec… • By now you may be thinking, “But Mr. G…didn’t you forget the transition metals?” • No. I did not. Chill. • They’re just weird.

  30. Transition Metals Groups 3 - 12: Transition Metals: Many transition metals have more than one oxidation state Iron (II) = Fe2+ Iron (III) = Fe3+

  31. Multivalent Elements • For transition elements (and some others), things can get tricky. • Most have either 1 or 2 valence electrons. • Some have more or less. • Some have more than one amount of valence electrons. • These are called multivalent metals because they have multiple valence numbers (charges). • They are often written as this: • Element (charge written as Roman numeral)

  32. Common Multivalent Elements • Copper (Cu) – either 1 or 2 valence electrons. • Copper (I) or Copper (II) – 1+ or 2+ • Nickel (Ni) – either 2 or 3 valence electrons. • Nickel (II) or Nickel (III) – 2+or 3+ • Iron (Fe) – either 2 or 3 valence electrons. • Iron (II) or Iron (III) – 2+or 3+ • Lead (Pb) – either 2 or 4 valence electrons. • Lead (II) or Lead (IV) – 2+or 4+ • Tin (Sn) – either 2 or 4 valence electrons. • Tin (II) or Tin (IV) – 2+or 4+ • Mercury (Hg) – either 1 or 2 valence electrons. • Mercury (I) or Mercury (II) – 1+ or 2+

  33. However… • Some transition elements have only one possible oxidation state. • Zinc (Zn) – Zn2+ • Silver (Ag) – Ag+

  34. Valence Electrons andMultivalent Metals • How many valence electrons does Iron (I) have? • One. • If it forms a +1 charge, it must have one electron to give up. • How many valence electrons does Lead (IV) have? • Four. • If it forms a +4 charge, it must have four electrons to give up.

  35. Nomenclature • Before we begin nomenclature, I’m going to hand out a flowchart to everyone. • Treat this piece of paper like it’s a piece of solid Au, or Pt. • Get it? • Anyway, this paper will save you a lot of frustration. Trust me.

  36. Nomenclature • We now reach something called nomenclature, which is a fancy name for a very particular naming system. • Ain’t that a coincidence?

  37. Nomenclature • When naming ionic compounds (that’s today’s lesson), cations’ names are not changed. • In other words, a sodium ion is called a “sodium ion.” • Anions, however, are referred to by the element stem followed by –ide. • Chlorine becomes chloride, nitrogen becomes nitride, fluorine becomes fluoride (becomes toothpaste). • Thus, NaCl is called “sodium chloride,” not “sodium chlorine” or “sodide chloride” or whatever.

  38. Procedure • For ionic compounds, follow these four steps: • Write the formulas for the cation and anion, including charges. Put polyatomic ions in a circle. Do not change anything in the circle. • Check to see if the charges are balanced (=0). • Balance charges, if necessary, using subscripts. • If you need more than one of a polyatomic ion, use parentheses at the end. ONLY for polyatomics! • Simplify subscripts, remove circles and charges to clean it all up.

  39. Remember the Goal • Your goal is to make sure that the positive parts of the compound are completely balanced with the negative ones. • In other words, the overall charge adds to 0.

  40. Quick Reminder Charge (1-) Nd2 - Subscript (2 Nd atoms)

  41. Example: Iron (III) chloride Fe 3+ Cl- 3 Total Negative Charge 1- Total Negative Charge 3- Total Positive Charge 3+ Not balanced! • Write the formulas for the cation and anion, including charges. • Check to see if the charges are balanced (=0). • Balance charges, if necessary, using subscripts. • Clean it up.

  42. Example: Barium nitrate Ba2+ ( ) NO3- 2 Total Negative Charge 2- Total Negative Charge 1- Total Positive Charge 2+ Not balanced! • Write the formulas for the cation and anion, including charges. Put polyatomic ions in a circle. • Check to see if the charges are balanced (=0). • Balance charges, if necessary, using subscripts. • If you need more than one of a polyatomic ion, use parentheses. ONLY for polyatomics! • Clean it up.

  43. About Parentheses • 2 + 3 x 4 = ? • 14 • (2 + 3) x 4 = ? • 20 • Parentheses make a difference only when you have multiple polyatomic ions. • (NO3)3 or (OH)2 are not the same as N3O9 and OH2 • Parentheses don’t make a difference if it’s just an atom or one polyatomic ion. • You write Cl2, not (Cl)2.

  44. Example: Ammonium sulfate ( ) NH4+ SO42- 2 Total Negative Charge 2- Total Positive Charge 2+ Total Positive Charge 1+ Not balanced! • Write the formulas for the cation and anion, including charges. Put polyatomic ions in a circle. • Check to see if the charges are balanced (=0). • Balance charges, if necessary, using subscripts. • If you need more than one of a polyatomic ion, use parentheses. ONLY for polyatomics! • Clean it up.

  45. Example: Aluminum sulfide Al3+ S2- 3 2 Total Negative Charge 2- Total Negative Charge 6- Total Positive Charge 3+ Total Positive Charge 6+ Not balanced! • Write the formulas for the cation and anion, including charges. • Check to see if the charges are balanced (=0). • Balance charges, if necessary, using subscripts. • Clean it up.

  46. Alternative Method: The Cross-Over S2- Al3+ 2 3

  47. Example: Magnesium carbonate Mg2+ CO32- Total Negative Charge 2- Total Positive Charge 2+ Are balanced! • Write the formulas for the cation and anion, including charges. Put polyatomic ions in a circle. • Check to see if the charges are balanced (=0). • Clean it up. Remember to simplify.

  48. Example: Zinc hydroxide Zn2+ ( ) OH- 2 Total Negative Charge 2- Total Negative Charge 1- Total Positive Charge 2+ Not balanced! • Write the formulas for the cation and anion, including charges. Put polyatomic ions in a circle. • Check to see if the charges are balanced (=0). • Balance charges, if necessary, using subscripts. • If you need more than one of a polyatomic ion, use parentheses. ONLY for polyatomics! • Clean it up.

  49. Example: Aluminum phosphate Al3+ PO43- Total Negative Charge 3- Total Positive Charge 3+ Are balanced! • Write the formulas for the cation and anion, including charges. Put polyatomic ions in a circle. • Check to see if the charges are balanced (=0). • Clean it up.

  50. Practice To practice all this stuff, let’s turn to the Nomenclature Practice Sheet worksheet, first page. Try the first section (1-12).