Bond Formation Chapter 8 (Glencoe)

1. Bond FormationChapter 8 (Glencoe) Chapter 5 (Zumdahl)

2. Atoms in contact will interact! • Based on electronegativity difference: • 1.8-3.3 ionic (metals with nonmetals) • 0.4-1.7 polar covalent (varying degrees) • 0.0-0.3 nonpolar covalent (2 nonmetals) • See page 169 • What about metals with other metals?

3. Brass White gold 14K gold Steel Cast iron Bronze Pewter Cu + Zn Au + Ni or Pd Au + Cu or Ag Fe + C Fe + C + Si Cu + Sn Sn + Cu or Sb or Pb Metallic atoms share their valence electrons freely in a “sea of electrons” to form alloys.

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5. Ionic Crystalline arrangement (brittle/will shatter) High melting and boiling temperatures Ratio of atoms involved is determined by charges Non-conductive unless molten, dissolved in water Covalent Molecular arrangement Lower melting and boiling temperatures (may even be gases!) Ratio of atoms involved is determined experimentally Generally non-conductive Properties of other bonding:

6. Crystal strength: • Determined by ionic radius • Smaller radii = higher lattice energy • Determined by ionic charge • Higher charge = higher lattice energy • KI < KF < LiF < MgO

7. Gemology vs Mineralogy: • http://gemologyproject.com/wiki/index.php?title=Introduction_to_Gemology • http://www.gia.edu/index.html • http://www.gemsociety.org/wow/wow.htm • http://www.minsocam.org/MSA/K12/groups/groups.html • Look for 4Cs • Classification of crystalline shape • Measure of hardness • Career possibilities

8. Predicting ionic ratios • Based on charge ratios (…and called “formula units”) • For example • Na 1+ and Cl 1- ; therefore, will combine 1:1 • NaCl “sodium chloride” • Na 1+ and S 2-; therefore, will combine 2:1 • Na2S “sodium sulfide” • Be 2+ and N 3-; therefore, will combine 3:2 • Be3N2 “beryllium nitride”

9. D-block cations • Have varying “charges”, often called “oxidation states” • Charges of these elements are indicated with Roman numerals (Stock method) OR name changes (less common) • “-ic” means higher option (cupric = 2+) • “-ous” means lower option (cuprous = 1+)

10. Naming, too! • Naming binary ionic compounds is relatively easy • Simply, name the cation (including charge if a d-block metal) and the anion with “-ide” • Sodium chloride Gold (III) iodide • Beryllium oxide Zinc nitride

11. Polyatomic ions • A group of atoms acting as one cation or anion • Memorize the chart on page 224 • Yes, all of it—test next Thursday • Oxyanions—negatively charged polyatomic ion containing oxygen

12. Make another ‘A’ • Vocabulary • Memorize polyatomic ions • Read about alloys • Read about properties of ionic compounds • Practice writing formulas and names

13. Covalent bonding • Compounds involving nonmetals utilize prefixes to indicate numbers of atoms in the molecules: • CO2 = carbon dioxide • Note: no “mono” on first element, but required otherwise… • NO = nitrogen monoxide • N2O5 = dinitrogen pentoxide

14. Mono Di Tri Tetra Penta Hexa Hepta Octa Nono Deca One Two Three Four Five Six Seven Eight Nine Ten Prefixes:

15. Another exception: • Non-metals combined with hydrogen……are called “acids” • Therefore: • Monatomic anions = “hydro” + “-ic” • Hydrochloric acid HCl • Oxyanions = “ate” = “-ic” acid • Sulfuric acid H2SO4 • = “ite” = “-ous” acid • Nitrous acid HNO2

16. Whew!! Where do I start?