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Chemistry Chapter 7

Chemistry Chapter 7. Chemical Formulas and Chemical Compounds. Elements combine to form bonds. Covalent Bonds . Ionic Bonds. -Electrons are transferred -Usually between a metal and a non-metal or polyatomic ions EXAMPLE: sodium chloride. -Electrons are shared

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Chemistry Chapter 7

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  1. Chemistry Chapter 7 Chemical Formulas and Chemical Compounds

  2. Elements combine to form bonds Covalent Bonds Ionic Bonds -Electrons are transferred -Usually between a metal and a non-metal or polyatomic ions EXAMPLE: sodium chloride -Electrons are shared -Usually between two non-metals EXAMPLE: carbon dioxide Different systems of naming depending on the type of bond…BE CAREFUL!

  3. Ions • Cation:A positive ion • Mg2+, NH4+ • Anion:A negative ion • Cl-, SO42- • Ionic Bonding:Force of attraction between oppositely charged ions.

  4. Predicting Ionic Charges Group 1: Lose 1 electron to form1+ions H+ Na+ K+ Li+

  5. Bohr Model of Sodium Protons: 11 × +1 = 11 Electrons: 11 Electrons: 10 × -1 = -11 × -1 = -10 How many electrons does Na have? What’s the net charge on Na? Now, how many electrons does Na have? How many protons does Na have? +1 0 Na + How many valence electrons does Na have? Now does Na satisfy the octet rule? Does Na satisfy the octet rule? How can we satisfy the octet rule?

  6. Predicting Ionic Charges Loses 2 electrons to form2+ions Group 2: Be2+ Mg2+ Ca2+ Ba2+ Sr2+

  7. Bohr Model of Magnesium Protons: 12 × +1 = 12 What is the net charge of Mg? Electrons: 10 × -1 = -10 +2 Mg +2 How many valence electrons does Mg have? Now does Mg satisfy the octet rule? Does Mg satisfy the octet rule? How can we satisfy the octet rule?

  8. Predicting Ionic Charges Group 13: Loses 3 electrons to form 3+ ions B3+ Al3+ Ga3+

  9. Bohr Model of Aluminum Protons: 13 × +1 = 13 What is the net charge of Al? Electrons: 10 × -1 = -10 +3 Al +3 How many valence electrons does Al have? Now does Al satisfy the octet rule? Does Al satisfy the octet rule? How can we satisfy the octet rule?

  10. Predicting Ionic Charges Group 14: Lose 4 electrons or gain 4 electrons? Neither! Group 14 elements rarely form ions.

  11. Predicting Ionic Charges Nitride N3- Group 15: Gains 3 electrons to form3-ions P3- Phosphide As3- Arsenide

  12. Bohr Model of Phosphorous Protons: 15 × +1 = 15 What is the net charge of P? Electrons: 18 × -1 = -18 -3 P -3 How many valence electrons does P have? Now does P satisfy the octet rule? Does P satisfy the octet rule? How can we satisfy the octet rule?

  13. Predicting Ionic Charges Oxide O2- Group 16: Gains 2 electrons to form 2- ions S2- Sulfide Se2- Selenide

  14. Bohr Model of Sulfur Protons: 16 × +1 = 16 What is the net charge of S? Electrons: 18 × -1 = -18 -2 S -2 How many valence electrons does S have? Now does S satisfy the octet rule? How can we satisfy the octet rule? Does S satisfy the octet rule?

  15. Predicting Ionic Charges F1- Br1- Fluoride Bromide Group 17: Gains 1 electron to form1-ions Cl1- I1- Chloride Iodide

  16. Bohr Model of Chlorine Protons: 17 × +1 = 17 What is the net charge of Cl? Electrons: 18 × -1 = -18 -1 Cl -1 How many valence electrons does Cl have? Now does Cl satisfy the octet rule? Does Cl satisfy the octet rule? How can we satisfy the octet rule?

  17. Predicting Ionic Charges Stable Noble gases do notform ions! Group 18:

  18. Pause for a Cause #1What is the oxidation number of each of the following elements?BaAlSBrNFK

  19. Predicting Ionic Charges Groups 3 - 12: Many transitionelements have more than one possible oxidation state. Iron (II) = Fe2+ Iron (III) = Fe3+

  20. Predicting Ionic Charges Groups 3 - 12: Sometransitionelements have only one possible oxidation state. Memorize Zinc = Zn2+ Silver = Ag+ Cadmium = Cd2+

  21. Polyvalent Elements and Their Chargesto Memorize Polyvalent Element Symbol Charge Cu Copper +1,+2 Pb +2,+4 Lead Fe +2,+3 Iron +1,+2 Hg,Hg2 Mercury +2,+4 Sn Tin Chromium Cr +2,+3 Cobalt Co +2,+3 Nickel Ni +2,+3 Manganese Mn +2,+3

  22. Polyatomic Ions to Memorize! -2 +1 -1 Acetate C2H3O2 -1 Bromate BrO3 -1 Chlorate ClO3 -1 Chlorite ClO2 -1 Cyanide CN -1 Bicarbonate HCO3 -1 Hydroxide OH -1 Nitrate NO3 -1 Nitrite NO2 -1 Iodate IO3 -1 Permanganate MnO4 Hydrogen Sulfate HSO4 Ammonium NH4 +1 Carbonate CO3 -2 Chromate CrO4 -2 Dichromate Cr2O7 -2 Oxalate C2O4 -2 Peroxide O2 -2 Sulfate SO4 -2 Sulfite SO3 -2 -3 Arsenate AsO4 -3 Phosphate PO4 -3 Hand out Table

  23. Writing Ionic Compound Formulas Example:Barium nitrate 1. Write the formulas for the cation and anion, including CHARGES! 2. Check to see if charges are balanced.(If so, skip to step 5) 3.Balance charges , if necessary, usingsubscripts. A. Cross over the charges by using the absolute value of each ion’s charge as the subscript for the other ion. B. Use parentheses if youneed more than oneof apolyatomic ion. - Ba(NO3)2 () 2+ Ba NO3 2 4. Check the subscripts and divide them by their largest common factor to give the smallest possible whole-number ratio. Not balanced! 5. Write the formula without the charges.

  24. Writing Ionic Compound Formulas Example:Ammonium sulfate 1. Write the formulas for the cation and anion, including CHARGES! 2. Check to see if charges are balanced.(If so, skip to step 5) 3.Balance charges , if necessary, usingsubscripts. A. Cross over the charges by using the absolute value of each ion’s charge as the subscript for the other ion. B. Use parentheses if youneed more than oneof apolyatomic ion. + 2- (NH4)2SO4 ( ) NH4 SO4 2 Not balanced! 4. Check the subscripts and divide them by their largest common factor to give the smallest possible whole-number ratio. 5. Write the formula without the charges.

  25. Let’s Practice1. potassium nitrate2. sodium sulfate3. calcium hydroxide4. ammonium sulfite5. calcium phosphate6. aluminum chromate7. lithium bromide8. sodium peroxide

  26. Pause for a Cause #2Page 251 16. Write formulas for each of the following compounds: • sodium fluoride • calcium oxide • potassium sulfide • magnesium chloride • aluminum bromide • lithium nitride

  27. Writing Ionic Compound Formulas Example: Copper II carbonate • Write the formulas for the cation and anion, including • CHARGES! 2. Check to see if charges are balanced. (If so, skip to step 5) 5. Write the formula without the charges. CuCO3 Cu2+ CO32- They are balanced!

  28. Writing Ionic Compound Formulas Names ending in –ide usually, but not always, represent an element from the periodic table. Example:Iron (III) chloride 1. Write the formulas for the cation and anion, including CHARGES! 2. Check to see if charges are balanced.(If so, skip to step 5) 3.Balance charges , if necessary, usingsubscripts. A. Cross over the charges by using the absolute value of each ion’s charge as the subscript for the other ion. B. Use parentheses if youneed more than oneof apolyatomic ion. - 3+ FeCl3 Fe Cl 3 4. Check the subscripts and divide them by their largest common factor to give the smallest possible whole-number ratio. Not balanced! 5. Write the formula without the charges.

  29. Writing Ionic Compound Formulas Example: Chromium III sulfide 1. Write the formulas for the cation and anion, including CHARGES! 2. Check to see if charges are balanced. (If so, skip to step 5) 3.Balance charges , if necessary, using subscripts. A. Cross over the charges by using the absolute value of each ion’s charge as the subscript for the other ion. B. Use parentheses if you need more than one of a polyatomic ion. 2- 3+ Cr S Cr2S3 2 3 Not balanced! 4. Check the subscripts and divide them by their largest common factor to give the smallest possible whole-number ratio. 5. Write the formula without the charges.

  30. Let’s Practice • Write formulas for each of the following compounds. • Chromium III hydroxide • Mercury I chloride • Tin IV chloride • Iron II chromate • Cobalt II sulfide • Copper I sulfate • Iron III oxide

  31. Pause for a Cause #3Writing Formulas of Compounds that have Roman Numerals Write the formulas for the following compounds: • Lead II nitrate • Iron II Sulfite • Mercury I Chloride • Tin II Chlorate • Chromium III Dichromate • Mercury II Phosphate • Cobalt II Acetate

  32. Naming Covalent Binary Compounds • -Compounds between twononmetals • -First element in the formula isnamed first. • - Second element is named as if it were an • anion. • - Use prefixes • - Only usemonoon second element -

  33. 1 – mono 2 – di 3 – tri 4 – tetra 5 - penta 6 – hexa 7 – hepta 8 – octa 9 – nona 10 – deca diphosphoruspentoxide P2O5 = CO2 = carbon dioxide CO = carbonmonoxide dinitrogenmonoxide N2O =

  34. If given the formula…….. • 1st determine if the compound is a binary (molecular) compound • If all the elements in the compound are non-metals or metalloids the compound is a binary compound. • Use prefixes to name the compound. • CHARGES DON’T MATTER, DON’T WRITE CHARGES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! • DON’T SWITCH THE PREFIXES!!!!!!!!!!!!!!!!!!!!

  35. Pause for a Cause #4Write the formula of the following compounds(WRITE WHAT YOU SEE DO NOT CHECK OXIDATION STATE!) • Phosphorus Pentachloride • Carbon Tetrafluoride • Dinitrogen Pentaoxide • Tetraphosphorous Decaoxide • Carbon Monoxide • Carbon Disulfide

  36. Sourvelis’s Rules For Naming Look at the first element in the compound. If the first element is… 1. A group 1 or 2 metal, or if it is Ag, Zn, Al, Cd, simply name the compound. NaCl  Sodium Chloride 2. A transitional metal all the way to the left of the metalloid line, use roman numerals. Fe2O3  Iron (III) Oxide 3. A metalloid or nonmetal use prefixes. N2O5 Dinotrogen Pentoxide 4. is hydrogen name it like an acid. HCl  Hydrochloric acid. Exception Acetic acid C2H3O2H 5. a carbon atom, name it as an organic molecule. ex. C2H6  ethane Mixed Review Sheet

  37. Naming Ionic Compounds Using Rule 1 • 1. Cation first, then anion • 2. Monatomic cation = name of the element • Ca2+= calciumion • 3. Monatomic anion =root+-ide • Cl- =chloride • CaCl2 = calciumchloride 4. For polyatomic ions, use the name of that polyatomic ion.

  38. Let’s Practice!! Name the following compounds: • MgCl2 • Ag2O • Ca(OH)2 • SrS • KClO3 • NH4OH • KClO2 • Magnesium Chloride • Silver Oxide • Calcium Hydroxide • Strontium Sulfide • Potassium Chlorate • Ammonium Hydroxide • Potassium Chlorite

  39. Pause for a Cause #5 Name the following compounds: K2CrO4 Ca(MnO4)2 Zn(HCO3)2 Mg3N2 Na2O2 Ba3(PO4)2 AgCl

  40. If given the formula…….. • And the compound is not a binary compound, name the compound like an ionic compound. • Use roman numerals if the first element is a transitional element or to the left of the metalloid line. • (Exceptions Ag, Zn, Cd)

  41. Naming Ionic CompoundsUsing Roman Numerals Some metals have multiple oxidation states (Groups 3-12 and to the left of the metalloid line) • Example: • PbCl2 • Lead can be a Pb2+ or Pb4+ cation • PbCl2 = lead (II) chloride • How do you know???

  42. How do we know that lead was +2? -1 +2 The oxidation number of lead is +2. PbCl2 -2 What is the charge of chlorine ion? How many chlorine ions does PbCl2 have? What’s the total charge of the chlorine ions? Compounds are neutral, so what must the charge of lead be in order to balance the -2 charge of chlorine?

  43. Let’s try Fe2O3 +3 -2 The oxidation number of iron is +3. O Fe Iron III Oxide 3 2 -6 +6 What is the charge of oxygen ion? How many oxygen ions does Fe2O3 have? What’s the total charge of the oxygen ions? What must the charge of iron be in order to balance the -6 charge of the oxygens?

  44. Let’s practice!!! Name the following compounds: • CuO • CoF3 • SnI4 • FeS Copper II Oxide Cobalt III Fluoride Tin IV Iodide Iron II Sulfide

  45. If given the name….. • If the compound is not a binary compound (contains polyatomic ions), use the rules for writing ionic compounds. • Make sure to use the correct charges. • Make sure you don’t change the subscripts of the polyatomic ions. • THE ANSWER DOES NOT HAVE ANY CHARGES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

  46. Pause for a Cause #6 Name the following compounds: Pb(ClO3)2 Co2O3 Fe2(Cr2O7)3 NiBr2 MnSO4 SnO Hg2Cl2 Fe(HCO3)3

  47. If given the name….. • 1st check for prefixes. • If prefixes are present, the compound is probably a binary compound. • DON’T WORRY ABOUT CHARGES, DON’T WRITE CHARGES, JUST WRITE WHAT YOU SEE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! • ***Remember some polyatomic ions have prefixes (bicarbonate, dichromate, dimercury). Write these like ionic compounds.

  48. Pause for a Cause #7 Name the following compounds using prefixes: OF2 SiO2 SO3 P2O5 BF3 XeF4

  49. Quiz: Name the formula AgC2H3O2 FeCl3 N2O4 Cr2O3 FeCl2

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