2. Salt…NaCl 1.sea salt (sharper) vs. brine or rock salt 2.trade – for gold via Timbuktu and Saharan salt 3.fishing trips longer b/c you could preserve fish 4.wartime tactics – destroying saltworks 5.preserving foods 6.4 oz/body from meat…vegetarians need supplements 7.taxing …the gabelle…gandhi…british business 8. soda ash for soap 9. caustic soda for…extracting al, rayon, cellophane, soap, detergents, petro products, paper, etc. and 10. chlorine for disinfectants, pesticides, polymers and pharmaceuticals.

3. Chemicals that hurt Napoleon as he attacked then retreated from Moscow in winter: 1.Tin Sb: buttons changed to a weak tin 2. Salt NaCl: lack of dietary salt prevents wounds from healing 3. Ascorbic acid – Vitamin C - soldiers died of scurvy.

4. III. A polyatomic ion is a group of atoms that: 1. covalently bond to each other, but are 2. ionic bonded to metals. Ex. hydroxide OH - H shares an e- with O: covalent bond To form sodium hydroxide NaOH, the Na transfers an e- to OH: Na + + OH - = KOH  ionic solid H O

5. NaOH sodium hydroxide (aka lye or caustic soda) is used in: cleaning paper and soap making food prep

6. Ex. nitrate NO 3 -1 N O O O In potassium nitrate KNO 3, K transfers an e- to the nitrate. K + + NO 3 - = KNO 3  ionic solid covalent bonds

7. KNO 3 is used in: gunpowder tree stump removers toothpaste for sensitive teeth food preservative

8. IV. Metallic bonds - e- can leave the atoms  mobile (free) - leave behind a positive ion - negative sea + positive ions = metallic bond - mobile e-s make good conductors

9. positive ions

11. Summary: (M = metal, N = nonmetal) bond atom type Ex substance ionic M-N NaClionic solid covalent N-N H 2 Omolecule polyat. ions M-(N-N)CaCO 3 ionic/molecule metallic M Agmobile