Ions & ionic compounds

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  • @Alissa Miller go through it once more
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  • @Alissa Miller lol
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  • Hi, is it possible to explain why chlorine is named iodide in slide 52 and not say tetrachloride? I'm just a little confused where you got the name iodide from. I'm sure there's an explanation, I just don't know it :)
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Ions & ionic compounds

  1. 1. Ions & Ionic Compound
  2. 2. Compounds <ul><li>A compound is a pure substance made up of two or more elements in which the elements are chemically combined </li></ul>+ = Na Cl NaCl
  3. 3. Compounds <ul><li>Two types of compounds: Ionic and Molecular </li></ul><ul><li>Ionic compounds: composed of positive and negative ions </li></ul>
  4. 4. Ion <ul><li>An ion is an atom or group of atoms that has either a positive charge or a negative charge </li></ul>
  5. 5. Ion <ul><li>Ions form when atoms gain or lose electrons to become stable </li></ul><ul><li>A atom is stable when the valence shell is full </li></ul>
  6. 6. Positive Ion Example <ul><li>Sodium loses one electron to become stable </li></ul><ul><li>Results in an ion that has a positive charge </li></ul>= Na x
  7. 7. Positive Ion Example <ul><li>The symbol “+” is written as a superscript to indicate that the sodium has a charge of 1+ </li></ul>Na +
  8. 8. Negative Ion Example <ul><li>Chlorine gains one electron to become stable </li></ul><ul><li>Results in an ion with a negative charge </li></ul>= Cl
  9. 9. Negative Ion Example <ul><li>The symbol “-” is written as a superscript to indicate that the chlorine ion has a charge of 1- </li></ul>Cl -
  10. 10. Ion <ul><li>Both ions have a full valence shell containing the maximum number of electrons possible </li></ul><ul><li>This new arrangement of valence electrons has less energy than the previous arrangement and is stable </li></ul>
  11. 11. Cation <ul><li>When an atom gives up one or more electrons it becomes positive </li></ul><ul><li>Called a cation “cat-eye-on” </li></ul>
  12. 12. Anion <ul><li>When an atom gains one or more electron it become negative </li></ul><ul><li>Called an anion (“an-eye-on”) </li></ul>
  13. 13. Ion <ul><li>Ca + ions are posi + ive </li></ul>A n ions are n egative
  14. 14. Writing Ion Symbols <ul><li>Write the symbol of the element and show the ion charge as a superscript </li></ul><ul><li>Example: the symbol of a calcium ion is Ca 2+ </li></ul><ul><li>When an ion has a charge of 1+ or 1- the symbol has no number in the superscript, such as Na + or F - </li></ul>
  15. 15. Naming Univalent Cations <ul><li>When an element can form only one type of ion, the ion has the same name as the element </li></ul><ul><li>Eg: Ca 2+ = calcium ion </li></ul>Ca 20p 20n +2
  16. 16. Naming Multivalent Cations <ul><li>A multivalent element is an element that can form an ion in more than one way </li></ul><ul><li>Example: An atom of copper can form two different ions: Cu + or Cu 2+ </li></ul>
  17. 17. Naming Multivalent Cations <ul><li>The name of an ion of a multivalent element always contains a Roman numeral that indicates the ion charge </li></ul><ul><li>I = 1 </li></ul><ul><li>II = 2 </li></ul><ul><li>III = 3 </li></ul><ul><li>IV = 4 </li></ul><ul><li>V = 5 </li></ul><ul><li>VI = 6 </li></ul>
  18. 18. Naming Multivalent Cations <ul><li>For example, Cu+ is named copper(I) (read as “copper one”) </li></ul><ul><li>Cu2+ is named copper(II) (read as “copper two”) </li></ul><ul><li>Only multivalent metals have Roman numerals in their names </li></ul>
  19. 19. Naming Anions <ul><li>A nonmetal that has gained electrons to become an ion has the the same name as the element but with the ending changed to -ide </li></ul><ul><li>Eg: Cl - = chloride ion </li></ul>
  20. 20. Naming Anions iod ide  iod ine brom ide  brom ine chlor ide  chlor ine sulf ide  sulf ur phosph ide  phosph orous fluor ide  fluor ine ox ide  ox ygen nitr ide  nitr ogen
  21. 21. Ion Reactivity <ul><li>Metal atoms tend to lose electrons </li></ul><ul><li>Non-metal atoms tend to gain electrons </li></ul>
  22. 22. Ion Reactivity <ul><li>The farther the valence electron is from its positive nucleus, the more easily it is removed and the more reactive the atom is </li></ul>
  23. 23. Cation Reactivity <ul><li>Reactivity generally increases for cations as you move down the periodic table </li></ul><ul><li>Example: potassium is more reactive than sodium </li></ul>Lithium Sodium Potassium Rubidium Cesium
  24. 24. Cation Reactivity reactivity increases Li K Na
  25. 25. Cation Reactivity <ul><li>Reactivity generally increases for cations as you move down the periodic table. </li></ul><ul><li>But why? </li></ul>Electrons that are further away from the nucleus are more easily lost. Thus atoms with more orbitals will be more reactive. Li K Na
  26. 26. Anion Reactivity <ul><li>Reactivity generally decreases for anions as you move down the periodic table </li></ul><ul><li>Example: fluorine is more reactive than chlorine </li></ul>Fluorine Bromine Iodine Astatine Chlorine
  27. 27. Anion Reactivity reactivity increases Cl F
  28. 28. Anion Reactivity <ul><li>Reactivity generally decreases for anions as you move down the periodic table </li></ul><ul><li>But why? </li></ul>Elements whose valence shell is closer to the nucleus will gain electrons more readily because they are closer to the nucleus. Negative electrons have a stronger attraction for the positive nucleus when the valence shell is closer to the nucleus. Cl F
  29. 29. A metal atom that has lost electrons (cation) and a nonmetal atom that has gained electrons (anion) will have the same number of electrons as its nearest noble gas .
  30. 30. Cations <ul><li>An metal atom that has lost electrons (cation) will have the same number of electrons as its nearest noble gas. </li></ul>
  31. 31. <ul><li>For example, neon is the closest noble gas in the periodic table to sodium, magnesium and aluminum </li></ul>Cations
  32. 32. Cations <ul><li>The cations Na + , Mg 2+ , and Al 3+ all have the same number of electrons as atoms of neon. </li></ul><ul><li>This relationship is known as being isoelectronic (having the same number of electrons). </li></ul>Na 11p 12n +1 Al 13p 14n +3 Mg 12p 12n +2 Ne 10p 10n
  33. 33. Anions <ul><li>Apply concept to anions </li></ul><ul><li>For example, neon is the closest noble gas in the periodic table to nitrogen, oxygen and fluorine </li></ul>
  34. 34. Isoelectronic <ul><li>Prove that these atoms are isoelectronic by drawing the Bohr diagrams. </li></ul>F - O 2- N 3- Ne
  35. 35. Ionic Compounds <ul><li>In general, an ionic compound consists of a metal and nonmetal </li></ul><ul><li>It is more accurate to say that ionic compounds form when atoms of different elements transfer electrons resulting in ions of opposite charges. </li></ul><ul><li>Thus there is always an electron donor and acceptor. </li></ul>
  36. 36. Ionic Compound <ul><li>For example, this process occurs when atoms of sodium metal (Na) combine with atoms of chlorine (Cl) to form sodium chloride (NaCl), or table salt </li></ul>+ = Na Cl NaCl
  37. 37. Ionic Compound <ul><li>During the formation of NaCl, one electron is transferred from a sodium atom to a chlorine atom </li></ul>
  38. 38. Ionic Compound <ul><li>In general, a cation will react with an anion to acquire a full valence shell </li></ul>
  39. 39. Ionic Compound <ul><li>The attraction between the cation and the anion is known as an ionic bond . This bond is what holds the ionic compound together. </li></ul>
  40. 40. Properties of Ionic Compound <ul><li>At room temperature, most are hard, brittle solids that can be crushed </li></ul>
  41. 41. Properties of Ionic Compound Ionic compounds form crystals that have an alternating arrangement of positively charged ions and negatively charged ions, so that when they break their edges are well-defined
  42. 42. Properties of Ionic Compound <ul><li>In an ionic crystal, every ion is attracted to every other ion in the crystal. As a result, ionic crystals have very high melting points </li></ul><ul><li>ex.) NaCl melts at 800 o C </li></ul>
  43. 43. Properties of Ionic Compound <ul><li>When an ionic compound dissolves in water, the crystal structure breaks down and the ions become free to move. </li></ul>
  44. 44. Properties of Ionic Compound <ul><li>Solutions of ionic compounds can conduct electricity </li></ul>
  45. 45. Naming Univalent Ionic Compounds <ul><li>Univalent Ionic Compounds are compounds where the metal ion only has one possible charge. </li></ul>
  46. 46. Naming Univalent Ionic Compounds <ul><li>Name the metal ion first </li></ul><ul><ul><li>The name of the metal ion is the same as the element name </li></ul></ul><ul><ul><li>Example: in KBr, the name of the K + ion is potassium </li></ul></ul><ul><li>Name the non-metal ion second </li></ul><ul><ul><li>When a non-metal becomes a negative ion, the ending of its name changes to “ide” </li></ul></ul><ul><ul><li>Example: a bromine atom become bromide ion (Br - ) </li></ul></ul><ul><li>The formulas of ionic compounds often contain numbers called subscripts which can be ignored when determining the name. </li></ul><ul><ul><li>Example: Na 3 P is sodium phosphide </li></ul></ul>
  47. 47. Naming Univalent Ionic Compounds <ul><li>Example Problem 1: </li></ul><ul><li>Write the name of the ionic compound ZnF 2 </li></ul><ul><li>Name the metal ion: </li></ul><ul><ul><li>Zn forms only one type of ion (Zn 2+ ), so the name is zinc </li></ul></ul><ul><li>Name the non-metal ion: </li></ul><ul><ul><li>The atom is fluor ine so the ion is fluor ide </li></ul></ul><ul><li>Combine the names: </li></ul><ul><ul><li>ZnF 2 = zinc fluoride </li></ul></ul>
  48. 48. Naming Multivalent Ionic Compounds <ul><li>Multivalent Ionic Compounds are compounds where the metal ion only has two or more possible charges. </li></ul>
  49. 49. Naming Multivalent Ionic Compounds <ul><li>Identify all the possible charges of the ions. </li></ul><ul><ul><li>Example: FeO </li></ul></ul><ul><ul><li>Fe can be Fe 2+ or Fe 3+ </li></ul></ul><ul><ul><li>O is O 2- </li></ul></ul><ul><li>Determine which charge on the multivalent ion is needed to make the compound neutral </li></ul><ul><ul><li>Example: Need to use Fe 2+ to balance O 2- </li></ul></ul>
  50. 50. RULE: <ul><li>Although ionic compounds are made of charged particles , the compound itself has no net charge </li></ul><ul><li>All ion charges of an ionic compound must add up to zero </li></ul><ul><li>The positive and negative charges in an ionic compound must be equal </li></ul>
  51. 51. Naming Multivalent Ionic Compounds <ul><li>Identify all the possible charges of the ions. </li></ul><ul><ul><li>Example: FeO </li></ul></ul><ul><ul><li>Fe can be Fe 2+ or Fe 3+ </li></ul></ul><ul><ul><li>O is O 2- </li></ul></ul><ul><li>Determine which charge on the multivalent ion is needed to make the compound neutral </li></ul><ul><ul><li>Example: Need to use Fe 2+ to balance O 2- </li></ul></ul><ul><li>Name the metal ion indicating the charge in brackets using Roman numerals </li></ul><ul><ul><li>1 = I , 2 = II , 3 = III , 4 = I V, 5 = V </li></ul></ul><ul><li>Name the non-metal ion changing the ending to ‘ide’ </li></ul><ul><ul><li>Example: FeO = Iron ( II ) oxide </li></ul></ul>
  52. 52. Naming Multivalent Ionic Compounds <ul><li>Example Problem 2: </li></ul><ul><li>Write the name of the ionic compound MnCl 4 </li></ul><ul><li>Identify the ions that form the compound: Mn 2+ or Mn 4+ and Cl - </li></ul><ul><li>Determine the charge of the multivalent ion that would make the compound neutral. </li></ul><ul><ul><li>Cl 4 means there are 4 x Cl - = a total charge of 4- </li></ul></ul><ul><ul><li>Would need to use Mn 4+ </li></ul></ul><ul><li>Name the metal ion indicating the charge using Roman numerals in brackets and adding the nonmetal –ide. </li></ul><ul><ul><li>Manganese ( I V) iodide </li></ul></ul>
  53. 53. Polyatomic Ions <ul><li>Poly = 2 or more </li></ul><ul><li>Atomic = atoms </li></ul><ul><li>A polyatomic ion is a group of atoms, usually of different elements, that act as a single ion </li></ul><ul><li>Example: one atom of sulphur and four atoms of oxygen form the polyatomic ion called sulphate, or SO42- </li></ul>
  54. 54. Polyatomic Ions <ul><li>Similar polyatomic ions are named using the suffixes “-ate” or “-ite” </li></ul><ul><li>Example: NO3- is nitrate; NO2- is nitrite </li></ul><ul><li>Most common polyatomic ions have a negative charge </li></ul><ul><li>However, the ammonium ion NH4+ has a positive charge </li></ul>
  55. 55. Polyatomic Ions SO 3 2- sulphite SO 4 2- sulphate PO 3 3- phosphite PO 4 3- phosphate MnO 4 - permanganate NO 2 - nitrite NO 3 - nitrate OH - hydroxide HCO 3 - bicarbonate CO 3 2- carbonate NH 4 + ammonium Formula Name
  56. 56. Naming Polyatomic Ionic Compounds <ul><li>Example Problem 3: </li></ul><ul><li>Write the name of the ionic compound LiHCO 3 </li></ul><ul><li>Name the metal/positive ion: </li></ul><ul><ul><li>Example: Li + = lithium </li></ul></ul><ul><li>Identify the polyatomic ion (use table): </li></ul><ul><ul><li>Example: HCO 3 - = hydrogen carbonate </li></ul></ul><ul><li>Combine the names. Do not change the polyatomic ending. </li></ul><ul><ul><li>LiHCO 3 = lithium hydrogen carbonate </li></ul></ul>
  57. 57. Writing Chemical Formula for Uni & Multivalent Ionic Compounds <ul><li>Identify the charge of the ions in the compound </li></ul><ul><ul><li>Example: Calcium chloride </li></ul></ul><ul><ul><li>Ca 2+ and Cl - </li></ul></ul><ul><li>Determine the number of positive and negative ions needed to make the compound neutral </li></ul><ul><ul><li>Need 2 Cl - to balance 1 Ca 2+ </li></ul></ul><ul><li>Write the metal atom first. Use subscript to indicate the number of ions if it is more than 1. Make sure to use on the lowest common multiple. </li></ul><ul><ul><li>Calcium chloride = CaCl 2 </li></ul></ul><ul><ul><li>Wrong: Ca 2 Cl 4 </li></ul></ul>
  58. 58. Writing Chemical Formula for Uni & Multivalent Ionic Compounds <ul><li>Example Problem 4 : </li></ul><ul><li>Write the chemical formula for Bismuth (V) Phosphide. </li></ul><ul><li>Bi 5+ and P 3- </li></ul><ul><li>How many of each do we need to make the compound neutral? </li></ul><ul><li>Write the chemical formula using subscripts as needed. </li></ul>
  59. 59. Writing Chemical Formula for Polyatomic Ionic Compounds <ul><li>Identify the charge of the ions in the compound </li></ul><ul><ul><li>Example: Calcium chlorate </li></ul></ul><ul><ul><li>Ca 2+ and ClO 4 - </li></ul></ul><ul><li>Determine the number of positive and negative ions needed to make the compound neutral </li></ul><ul><ul><li>Need 2 ClO 4 - to balance 1 Ca 2+ </li></ul></ul><ul><li>Write the metal atom first. If subscripts are needed for the polyatomic ion, place a bracket around it first. Make sure to use on the lowest common multiple. </li></ul><ul><ul><li>Calcium chlorate = Ca(ClO 4 ) 2 </li></ul></ul>
  60. 60. Writing Chemical Formula for Polyatomic Ionic Compounds <ul><li>Example Problem 5 : </li></ul><ul><li>Write the chemical formula for arsenic (III) acetate. </li></ul><ul><li>As 3+ and C 2 H 3 O 2 - </li></ul><ul><li>How many of each do we need to make the compound neutral? </li></ul><ul><li>Write the chemical formula using subscripts and brackets as needed. </li></ul>

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