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Study guide for worksheets and exams

Study guide for worksheets and exams. Chapter study guide and recommended HW questions Under exam folder find a word document for each chapter we cover As we go I will be adding topics covered and recommended HW problems from end of chapter HW

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Study guide for worksheets and exams

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  1. Study guide for worksheets and exams • Chapter study guide and recommended HW questions • Under exam folder find a word document for each chapter we cover • As we go I will be adding topics covered and recommended HW problems from end of chapter HW • These will be helpful for worksheets and exams as well. • Please come see me during office hrs for extra help.

  2. First exam • Thursday October 17th • Covers chapters 1-3, no lab material unless it is part of the chapters mentioned. • Multiple choice, true or false and calculations questions. • Allowed is a cheat sheet, periodic table, calculator and the important tables. • If you have questions please email me or stop by to office hrs.

  3. The Octet rule octet rule: atoms will gain or lose electrons to achieve an outer electron arrangement identical to that of a noble gas. The octet rule: a main group element is especially stable when it possesses an octet of 8 e− in its outer shell. octet = 8 valence e−

  4. Periodic trend of ionic charges • Elements in the same group form ions of similar • charge. • Metals form cations. • For metals in groups 1A, 2A, and 3A, the group • number = the charge on the cation. • Nonmetals form anions. • For nonmetals in Groups 6A and 7A, the anion • charge = 8 – the group number.

  5. Relating Group Number to Ionic Charge for Groups 1A–3A Periodic trend of ionic charges the cation charge = the group number group 1A: M 1 valence e− M+ + e− M 2 valence e− M2+ + 2e− group 2A: M 3 valence e− M3+ + 3e− group 3A:

  6. Relating Group Number to Ionic Charge for Groups 6A and 7A Periodic trend of ionic charges the anion charge = 8 – group number group 6A: X 6 valence e− + 2e− X 2− charge = 8 – 6 = 2 group 7A: X 7 valence e− + e− X − charge = 8 – 7 = 1

  7. Periodic trend of ionic charges

  8. Periodic trend of ionic charges Metals with Variable Charge

  9. Electron Configurations and the Periodic Table FIGURE 2.8 The Blocks of Elements in the Periodic Table

  10. Transition metals ions • Chromium, Cr, 24 electrons: 1s22s22p63s23p64s23d4 • Cr+2 or Cr+3 • Manganese, Mn, 25 electrons: 1s22s22p63s23p64s23d5 • Mn+2 • Iron, Fe, 26 electrons: 1s22s22p63s23p64s23d6 • Fe+2 or Fe+3 • Cobalt, Co, 27 electrons: 1s22s22p63s23p64s23d7 • Co+2 or Co+3 • Nickel, Ni, 28 electrons: 1s22s22p63s23p64s23d8 • Ni+2 • Copper, Cu, 29 electrons: 1s22s22p63s23p64s23d9 • Cu+2 or Cu+ • Zinc, Zn, 30 electrons: 1s22s22p63s23p64s23d10 • Zn+2

  11. Common Ions in the Human Body

  12. Problem 3.9 • Mn2+ is an essential nutrient needed for blood clotting and the formation of the protein collagen. a. how many protons and electrons are found in a neutral Mn atom? B. How many electrons and protons are found in the cation Mn2+ c. write the electronic configuration of the element manganese and suggest which electrons are lost to form Mn2+ cation. • a. Mn = 25 protons, 25 electrons • b. Mn2+ = 25 protons, 23 electrons • c. 1s22s22p63s23p64s23d5 • The two 4s2 valence electrons would be lost to form Mn2+.

  13. Ionic vs covalent bonding • There are two different kinds of bonding: • Ionic bonds result from the transfer of electrons • from one element to another. • Covalent bonds result from the sharing of • electrons between two atoms.

  14. Ionic and Covalent Bonds Atoms form octets • to become more stable • bylosing, gaining, orsharingvalence electrons • by forming ionicor covalent bonds

  15. Covalent Bonding Covalent bonds are formed when two nonmetals combine, or when a metalloid bonds to a nonmetal. A molecule is a discrete group of atoms that share electrons.

  16. Ionic bonding Sodium metal and chlorine gas are both elements. Sodium chloride is an ionic compound composed of sodium ions and chloride ion

  17. Problem 3.1 Predict whether the bonds in the following species are ionic or covalent? • CO covalent b. CaF2 ionic c. MgO ionic d. Cl2 Covalent e. HF Covalent f. C2H6 covalent

  18. Ionic bonding • Ionic bonds form between: • A metal on the left side of the periodic table. • A nonmetal on the right side of the periodic table. sodium (Na).e- config: 1s2 2s2 2p63s1 Chlorine (Cl).e- config: 1s2 2s2 2p63s2 2p5 1s 2s 2p 3s 1s 2s 2p 3s 3p

  19. Ionic bonding • Ionic bonds form between: • A metal loses e to form a positive ion. • A nonmetal gains electron to form a negative ion. sodium (Na+).e- config: 1s2 2s2 2p6 Chlorine (Cl-).e- config: 1s2 2s2 2p63s2 2p6 1s 2s 2p 3s 1s 2s 2p 3s 3p

  20. Ionic Compounds The sum of the charges in an ionic compound must be zero overall.

  21. Ionic Bond Formation • Ions with positive charges are attracted to ions with negative charges. The attractive force between such ions holds them together and is called an ionic bond. • Ionic bonds Both atoms are changed into ions with noble gas configurations. The resulting ions are then attracted to each other.

  22. Ionic Compounds

  23. Ionic Compounds HOW TO Write a Formula for an Ionic Compound Identify which element is the cation and which is the anion. Step [1] • Metals form cations and nonmetals form anions. • Use the group number of a main group element • to determine the charge. K+ K Cl− Cl Ca2+ Ca O O2− metal nonmetal nonmetal metal group 1A group 7A group 2A group 6A

  24. Ionic Compounds HOW TO Write a Formula for an Ionic Compound Determine how many of each ion type is needed for an overall charge of zero. Step [2] • When the cation and anion have the same • charge, only one of each is needed. O2− + CaO Ca2+ K+ + KCl Cl− zero charge zero charge One of each ion is needed to balance charge.

  25. Ionic Compounds HOW TO Write a Formula for an Ionic Compound • When the cation and anion have different charges, • use the ion charges to determine the number of • ions of each needed. Ca2+ Cl− A +2 charge means 2 Cl−anions are needed. A -1 charge means 1 Ca2+ cation is needed. Cl− + CaCl2 Ca2+ 2 Cl− for each Ca2+

  26. Ionic Compounds HOW TO Write a Formula for an Ionic Compound To write the formula, place the cation first and then the anion, and omit charges. Step [3] Examples: KCl CaO CaCl2 • Use subscripts to show the number of • each ion needed to have a zero overall • charge. • When no subscript is written, it is assumed to be “1.”

  27. Naming Ionic Compounds Naming Cations Main group cations are named for the element from which they are formed. Na+ K+ Ca2+ Mg2+ calcium sodium potassium magnesium

  28. Naming Ionic Compounds Naming Cations Other cations can be named two ways: • Systematic name: Follow the name of the cation • by a Roman numeral in parentheses to indicate • its charge. Fe2+ Fe3+ iron(III) iron(II)

  29. Naming Ionic Compounds Naming Cations Other cations can be named two ways: • Common name: Use suffix “-ous” for the cation • with a smaller charge and suffix “-ic” for the • cation with a higher charge. Fe2+ Fe3+ ferrous ferric

  30. Naming Ionic Compounds Naming Cations

  31. Naming Anions Naming Ionic Compounds Anions are named by replacing the ending of the element name by the suffix “-ide.”

  32. Compounds of Main Group Metals Naming Ionic Compounds • Name the cation and then the anion. • Do not specify the charge on the ion. • Do not specify how many ions of each type are needed to balance charge. Na+ sodium F− fluoride NaF sodium fluoride + Mg2+ magnesium + MgCl2 magnesium chloride Cl− chloride

  33. Compounds of Metals with a Variable Charge Naming Ionic Compounds HOW TO Name an Ionic Compound That Contains a Metal with Variable Charge Give the name for CuCl2. Example Determine the charge on the cation. Step [1] 2 Cl−anions = −2 total negative charge CuCl2 Cu cationmust have a +2 charge to makethe overall charge zero

  34. Compounds of Metals with a Variable Charge Naming Ionic Compounds HOW TO Name an Ionic Compound That Contains a Metal with Variable Charge Name the cation and the anion. Step [2] • The cation is named one of two possible ways: Systematic Common cupric Cu2+ copper(II) • The anion changes ending of element name to “-ide” Cl− chloride

  35. Compounds of Metals with a Variable Charge Naming Ionic Compounds HOW TO Name an Ionic Compound That Contains a Metal with Variable Charge Write the name of the cation first, then the anion. Step [3] copper(II) chloride Answer = or cupric chloride

  36. Writing a Formula from the Name Naming Ionic Compounds HOW TO Derive a Formula from the Name of an Ionic Compound Write the formula for tin(IV) oxide. Example Identify the cation and anion and determine their charges. Step [1] tin(IV) oxide tin(IV) oxide Sn4+ O O2− Sn

  37. Writing a Formula from the Name Naming Ionic Compounds HOW TO Derive a Formula from the Name of an Ionic Compound Step [2] Balance charges. Two −2anions are needed for each +4 cation. O2− Sn4+ Write the formula with the cation first, and use subscripts to show how many of each ion is needed to have zero overall charge. Step [3] final answer = SnO2

  38. Question 3.59 • Write the formula for the ionic compound formed from each pair of elements • a. calcium and sulfur • (Ca2+) and (S2–) = CaS • b. aluminum and bromine • (Al3+) and (Br–) = AlBr3 • c. lithium and iodine • (Li+) and (I–) = LiI • d. nickel and chlorine • (Ni2+) and (Cl–) = NiCl2 • e. sodium and selenium • (Na+) and (Se2–) = Na2Se

  39. Question 3.72 • Name each ionic compound • a. KF • potassium fluoride • b. ZnCl2 • zinc chloride • c. Cu2S • copper(I) sulfide • d. SnO • tin(II) oxide e. AuBr3 gold(III) bromide f. Li2S lithium sulfide g. SnBr4 tin(IV) bromide

  40. Physical Properties of Ionic Compounds • Ionic compounds are crystalline solids with very high meltingand boiling points. • When ionic compounds dissolve in water, they • separate into cations and anions, increasing the conductivity of the solution. +  solution NaCl water

  41. Problem 3.21 • List five physical properties of ionic compounds. • Ionic compounds have high melting points • Ionic compounds have high boiling points. • They usually dissolve in water. • Their solutions conduct electricity • They form crystalline solids.

  42. Polyatomic Ions A polyatomic ion is a cation or anion that contains more than one atom.

  43. Polyatomic Ions Writing Formulas for Ionic Compounds withPolyatomic Ions • When a cation and anion of equal charge combine, only one of each ion is needed. Na+ + NaNO2 NO2− zero overallcharge SO42− + BaSO4 Ba2+ zero overallcharge

  44. Polyatomic Ions Writing Formulas for Ionic Compounds withPolyatomic Ions • When a cation and anion of unequal charge • combine, use the ionic charges to determine • the relative number of each ion that is needed. Mg2+ + Mg(OH)2 OH− zero overallcharge −1 charge means 1 Mg2+anion is needed. +2 charge means 2 OH− anions are needed.

  45. Naming Ionic Compounds with Polyatomic Ions Polyatomic Ions The same rules are followed for naming standard ionic compounds: • Name the cation and then the anion. • Do not specify the charge on the ions. • Do not specify how many ions of each type are • needed to balance charge. NaHCO3 Al2(SO4)3 sodium bicarbonate aluminum sulfate

  46. Question 3.79 • Name each ionic compound. • a. NH4Cl • ammonium chloride • b. PbSO4 • lead(II) sulfate • c. Cu(NO3)2 • copper(II) nitrate, • cupric nitrate • d. Ca(HCO3)2 • calcium bicarbonate or • calcium hydrogen carbonate • e. Fe(NO3)2 • iron(II) nitrate or ferrous nitrate

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