Salt…NaCl1. sea salt (sharper) vs. brine or rock salt2. trade – for gold via Timbuktu and Saharan salt 3. fishing trips longer b/c you could preserve fish4. wartime tactics – destroying saltworks5. preserving foods6. 4 oz/body from meat…vegetarians need supplements7. taxing …the gabelle…gandhi…british business8. soda ash for soap9. caustic soda for…extracting al, rayon, cellophane, soap, detergents, petro products, paper, etc. and10. chlorine for disinfectants, pesticides, polymers and pharmaceuticals.

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.

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

HO

NaOH sodium hydroxide(aka lye or caustic soda) is used in:cleaningpaper and soap makingfood prep

Ex. nitrate NO3-1

N

O

O

O

In potassium nitrate KNO3,

K transfers an e- to the nitrate.K+ + NO3

- = KNO3 ionic solid

covalentbonds

KNO3 is used in:

gunpowder

tree stump removers

toothpaste for sensitive teeth

food preservative

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

positiveions

Summary: (M = metal, N = nonmetal)

bond atom type Ex substance

ionic M-N NaCl ionic solid

covalent N-N H2O molecule

polyat. ions M-(N-N) CaCO3 ionic/molecule

metallic M Ag mobile