Chapter 5: Ions and Ionic Compounds

1. Chapter 5: Ions and Ionic Compounds

2. 5.1 Ions

3. Ion • Ion: an atom or group of atoms that has a charge as a result of losing or gaining one or more electrons

4. Cation • Ca+ion: positively charged ion • Formed from a metal atom losing electrons

5. Anion • Anion: negatively charged ion • Formed from a nonmetal atom gaining electrons

6. Ions -1 +1 -3 +2 0 -2 +/- 4 +3

7. Metals and Roman Numerals • Metals can have various charges, so you MUST specify which one you have! • The charge of a metal is indicated by a Roman Numeral. • Exceptions: Groups 1 & 2, Silver (Ag), and Zinc (Zn) have only one charge, so they do not get Roman numerals in their names! • Examples: 1.) Copper (II) = Cu+2 2.) Iron (III) = Fe+2

8. Practice: Metals and Roman Numerals • Name the following transition metal ions: 1.) Cr+2 2.) Cr+3 3.) Mn+2 4.) Mn+3 5.) Pt+2 6.) Pt+4

9. Practice: Metals and Roman Numberals • Name the following transition metal ions: 1.) Cr+2 Chromium (II) 2.) Cr+3 Chromium (III) 3.) Mn+2 Manganese (II) 4.) Mn+3 Manganese (III) 5.) Pt+2 Platinum (II) 6.) Pt+4 Platinum (IV)

10. Practice: Ions • Determine if the following ions are cations (metal) or anions (nonmetal): 1.) Calcium ion 2.) Nitrogen ion 3.) Potassium ion 4.) Bromine ion 5.) Oxygen ion 6.) Lead (IV) ion

11. Practice: Ions • Determine if the following ions are cations or anions: 1.) Calcium ion: cation 2.) Nitrogen ion: anion 3.) Potassium ion: cation 4.) Bromine ion: anion 5.) Oxygen ion: anion 6.) Lead (IV) ion: cation

12. Practice: Ions

13. Practice: Ions

14. Calculating #p and #e of Ions

15. Calculating #p and #e of Ions

16. Calculating #p and #e of Ions

17. Calculating #p and #e of Ions

18. Octet Rule • Octet Rule: Atoms lose or gain electrons to match the valence electron configuration of a noble gas. • Atoms gain or lose electrons because they want to be more stable. • Full valence shells = stable atoms

19. Electron Configurations of Ions 1.) Determine number of electrons 2.) Write electron configuration Example: Fluorine ion = F-1 Fluorine ion has 10 electrons Electron configuration is 1s22s22p6 Neon also has 10 electrons and has the same electron configuration, so F-1 and neon are isoelectronic.

20. Practice • Determine the electron configuration of the following ions and write which noble gas they are isoelectronic with. 1.) Lithium ion 2.) Magnesium ion 3.) Calcium ion

21. Practice • Determine the electron configuration of the following ions and write which noble gas they are isoelectronic with. 1.) Lithium ion (2 electrons): 1s2 isoelectronic with helium 2.) Magnesium ion (10 electrons): 1s22s22p6 isoelectronic with neon 3.) Calcium ion (18 electrons): 1s22s22p63s23p6 isoelectronic with argon

22. 5.2 Ionic Bonds and Ionic Compounds

23. Ionic Bond • Transfer of electrons • Metal + Nonmetal • Ions come together due to electrostatic attraction (opposites attract)

24. Examples Determine if the following compounds are ionic: • NaCl : metal and nonmetal = ionic • CO2 : metal and nonmetal = not ionic

25. Practice • Determine if the following compounds are ionic: 1.) CO 2.) MgCl2 3.) CaBr2 4.) H2O 5.) LiF

26. Practice • Determine if the following compounds are ionic: 1.) CO = nonmetal + nonmetal = not ionic 2.) MgCl2 = metal + nonmetal = ionic 3.) CaBr2 = metal + nonmetal = ionic 4.) H2O = metal + metal = not ionic 5.) LiF = metal + nonmental = ionic

27. Ionic Bond Na (1 valence e-) + Cl ( 7 valence e-)  Na+ ion (8 valence e-) + Cl- ion (8 valence e-): The result is a positively charged sodium ion (left) and a negatively chorline atom (right). Both have full outer shells! Soidum (on the left) loses its one valence electron to chlorine (on the right) http://www.visionlearning.com/library/module_viewer.php?mid=55

28. Crystal Lattice • Ionic compounds organize in characteristic crystal lattice of alternating positive and negative ions. • Unit Cell: The smallest portion of a crystal lattice that shows the three-dimensional pattern of the entire lattice. Image from: http://www.docbrown.info/page04/4_72bond2.htm

29. Lattice Energy • When ionic bonds are formed, the energy that is released is called the lattice energy. • Alternatively, you can think of it as the amount of energy required to break the ionic bonds of a compound.

30. Examples • Sodium chloride (NaCl) dissolves in water: low lattice energy • Magnesium oxide (MgO) does not dissolve in water: high lattice energy

31. Properties of Ionic Compounds • Solid at room temperature • High boiling/melting points • Dissolve in water • Conduct electricity • Hard (the crystal is able to resist a large force applied to it) • Brittle (applied force results in fracture, not dents)

32. How to Identify an Ionic Compound 1.) Identify the state of matter -should be a solid at room temperature 2.) Tap it -will not break (hard) OR -will fracture if it breaks (brittle) 3.) Heat it -will only melt at high temperatures 4.) Shock it -will conduct electricity 5.) Dissolve it in water -will dissolve in water

33. Is it Ionic? • You tap the crystal and they shatter but still retain their sharp edges. • You heat the substance and after 2-3 minutes of heating it does not melt. • It dissolves in water and conducts electricity.

34. Is it Ionic? • You tap the crystal and they shatter but still retain their sharp edges. Yes • You heat the substance and after 2-3 minutes of heating it does not melt. • It dissolves in water and conducts electricity.

35. Is it Ionic? • You tap the crystal and they shatter but still retain their sharp edges. Yes • You heat the substance and after 2-3 minutes of heating it does not melt. Yes • It dissolves in water and conducts electricity.

36. Is it Ionic? • You tap the crystal and they shatter but still retain their sharp edges. Yes • You heat the substance and after 2-3 minutes of heating it does not melt. Yes • It dissolves in water and conducts electricity. Yes

37. 5.3 Names and Formulas of Ionic Compounds

38. Writing Formulas Binary Ionic Compounds

39. Ionic Compounds • Metal + Nonmetal • Cation = positive charge • Anion = negative charge

40. Writing Ionic Formulas • Write the symbol of the cation. • Write the charge of the cation. • Write the symbol of the anion. • Write the charge of the anion.

41. 5. Criss-cross the charges and write as subscripts without the signs. 6. Rewrite the formula. 7. Reduce the subscripts. 8. Check your answer (the compound should be neutral).

42. Examples • Sodium oxide • Aluminum sulfide • Barium chloride • Magnesium oxide

43. Examples • Sodium oxide = Na2O • Aluminum sulfide = Al2S3 • Barium chloride = BaCl2 • Magnesium oxide = MgO

44. Recall:Metals & The Stock System • The metal will have its charge listed behind its name as a roman numeral in parentheses. • Example: Iron(III) bromide = FeBr3 • Exceptions: Groups 1&2, Ag, and Zn don’t have Roman numerals because they have only one charge!

45. Examples • Copper(II) chloride • Tin(IV) iodide • Chromium(III) oxide

46. Examples • Copper(II) chloride = CuCl2 • Tin(IV) iodide = SnI4 • Chromium(III) oxide = Cr2O3

47. Writing Formulas Polyatomic Ionic Compounds

48. Monatomic Ion • An ion made up of one atom.

49. Polyatomic Ion • A charged group of 2 or more covalently bonded atoms.

50. Writing Formulas with Polyatomic Ions • When writing the polyatomic ion, put parentheses around the formula. • When criss-crossing the charges, drop the subscript behind the parentheses.