Announcements

1. Announcements • Make corrections to your test. Your new grade will count as a quiz grade. • Due Monday • Missed work folder moved to 104, yellow bulletin board • Get extra help when you need it! • 3rd floor office, Mondays/Thursdays 3:30-4:30 or by appointment

2. Collected today: Ions Practice worksheet • I should already have your Week 13 Homework

3. Why are we doing this? • Elements in your life? • What are most things made of? • Atoms and ions combine to make compounds. (December, January…) • Compounds combine and react to make new compounds. (Next semester)

4. Bonding

5. Electronegativity • How strongly an atom attracts other electrons in a chemical bond • Increases going up a group • In lower periods, valence electrons are further from the nucleus, less “pull” from the protons • Increases going across a period • Electrons on the same energy level are more strongly “pulled” by the nucleus • Same as ionization energy!!

6. Atomic Radius Increases Atomic Radius Increases

7. Electronegativity Increases Electronegativity Increases

8. chemical bond: strong electronic attraction between atoms • decreases the potential energy of an atom; makes it more stable • only the valence electrons are involved!

9. Three Types of Bonds • Bond type depends on electronegativity (e-neg) • Ionic Bond: very different e-negs. one metal, one non-metal • Covalent Bond: both e-negs. very high two non-metals • Metallic Bond: both e-negs. low one or more metals

10. Non-metals Metals

11. Anions Cations

12. High E-neg Low E-neg

13. Ionic Bond 1 from here 1 from here

14. Covalent Bond ≥2 from here

15. Metallic Bond ≥1 from here

16. Ionic Bonds • metal + non-metal • Low e-neg. + high e-neg. • Transfer e- from one atom to another. • Form cation + anion • Ions are attracted to one another

19. Cl sodium and chlorine • sodium transfers its electron to chlorine Na

21. Ionic or Covalent Bond? • Na and Cl • O and F • Ca and Cl • Mg and Br • N and O • Al and I • O and P • K and O

22. Ionic vs. Covalent Bonds: Modeling

23. Ionic Bond Vocabulary

24. Chemical formula: shows the kind and number of atoms in the smallest unit of the compound. • Ex: H2O, NaCl, C6H12O6

25. Law of Definite Proportions: In any chemical compound, the masses of the elements are in the same proportions. • Ex: If you had 100.00 g of magnesium sulfide, you would always have 43.13 g of magnesium and 56.87 g of sulfur. • Magnesium chloride always has 1 atom of Mg to 2 atoms of chlorine.

26. Structure of Ionic Compounds: • Crystal Lattice or Array • LOTS and LOTS of ions all attracted to one another • Ex: Salt = NaCl • One Na atom for every Cl atom in a huge lattice

28. Formula unit: The formula for an ionic compound. • The lowest whole-number ratio of ions in the compound. • Ex: NaCl = 1:1 ratio of sodium to chlorine • Ex: MgCl2 = 1:2 ratio of magnesium to chlorine

29. Writing Formulae for Ionic Compounds

30. Homework

31. Polyatomic ions: most covalently bonded, but have an overall electronic charge

32. Naming Ionic Compounds • chromium(III) hydroxide • copper(II) fluoride • Ca3(PO4)2 • calcium phosphate • anion ending …ide • Cr(OH)3 • CuF2 • Ca2+ PO43-

33. Crystal Lattice (Array) • structure of an ionic bond • each anion is surrounded by cations and vice versa

34. Announcements • Missing work on spreadsheet on yellow bulletin board  • Progress Reports submitted Friday only if your grade is… • Failing • Increased by 10% or more  • Decreased by 10% or more 

35. Properties of Ionic Compounds • hard • brittle (break easily) • solid • high melting/boiling points • do not conduct electricity as solids • conduct electricity when dissolved in water (aq) or molten (melted into a liquid) - electrolyte • more soluble in water than in other solvents

37. Ionic Compunds with Transition Metals

38. Transition Metals

39. Transition Metals • Transition Metals: metals in groups 3-12 • Can form ions with different charges • Ex: Copper Cu+ Cu2+ • Ex: Iron Fe2+ Fe3+

40. How do you know which ion is formed? • Stock System: Indicates which charge a transition metal ion has • Uses Roman Numerals to show charge • I = 1+ • II = 2+ • III = 3+ • IV = 4+ • V = 5+

41. Oxidation States (Ions) of V • http://www.youtube.com/watch?v=j-EaUHa_nuk&feature=PlayList&p=7E0E03ABA98A34AD&playnext=1&playnext_from=PL&index=19

42. http://www.youtube.com/watch?v=j-EaUHa_nuk&feature=PlayList&p=7E0E03ABA98A34AD&playnext=1&playnext_from=PL&index=19http://www.youtube.com/watch?v=j-EaUHa_nuk&feature=PlayList&p=7E0E03ABA98A34AD&playnext=1&playnext_from=PL&index=19

43. Some hints: • Stock system is ONLY used for cations that are transition metals • Cu, Fe, Hg, Pb, Sn, Cr, Mn, Co • Roman numeral comes AFTER cation. • Anions NEVER have Roman numerals.

44. Examples

45. Covalent Bonding • two or more non-metals • atoms share some valence electrons (not transfer)

46. Covalent Bonding • two or more non-metals • atoms share some valence electrons (not transfer) • single covalent bond: shares one pair of electrons • double: 2 pairs of e- • triple: 3 pairs of e-

47. F • usually each atom donates (gives) one of each pair of electrons • dative covalent bond: sometimes one atom donates both electrons Electron Pair Shared by both atoms Each e- donate by each atom F

48. number of bonds formed depends on the number of e- required to fill the valence shell • noble gases = full valence, rarely form compounds • octet rule: usually, atoms want 8 valence e- (H, He need 2)

49. Ex: C has 4 valence e- • needs 4 more to form a full octet • C forms 4 bonds • Ex: F has 7 valence e- • needs 1 more to form a full octet • F makes one bond • Nitrogen?

50. Bonding between C and F F F C F F F F C F F C F F F F structural hybrid Lewis formula diagram diagram =e- pair F e- C e- =covalent bond