CH2: Chemical Bonds

Types of Bonds  Covalent Bonds (nonmetals)  Electrons are shared  CH 4  Ionic Bonds (metal + nonmetal)  Gain/lose electrons  NaCl  Metallic Bond (only metals)  Valence electrons flow through the atoms  Sea of electrons  Au

Monatomic vs Diatomic Elements  Monatomic elements  These elements exist on their own as atoms  All the noble gases are monatomic  Diatomic elements  These elements exist in pairs  H 2 F 2 O 2 N 2 Cl 2 Br 2 I 2  Mr. H FONCl BrI

H. FONCl BrI

Lewis Dot Structures  Use the valence electrons to draw dots around elements and compounds.  Count valence e - total, fulfill octets of the outer elements, fulfill octet of central atom  If too many e -, put extra electrons on central atom  If not enough e -, use double/triple bonds  Groups have the same Lewis Dot Structures  Ex: F Cl Br

AlCO CO 2

HOMEWORK #3   CST CH 2 booklet, standards 2a-2g;   pg #1-30

CH 3: Conservation of Matter and Stoichiometry No calculators 

 Always balance equations  Helps eliminate wrong ones right away!

 1 mole = 6.02 x atoms, molecules, representative particles, ions  1 mole of any atom/molecule = periodic table mass = 6.02 x 10 23

Mole Bridge gramsmoles Molecules Divide by periodic table mass x 6.02 x Divide by 6.02 x x periodic table mass

Look for simple ratios!!!  0.5 moles = how many molecules?  2 moles equals how many grams of NaCl?  How many moles is grams of PbCl 2 ? (with no calculator!!)  How many atoms in g of CaCl 2 ?

Volume  Volume of a gas at STP  1 mole = 22.4 L  Or use PV = nRT

Stoichiometry Have 46 grams of Na reacting with unlimited Cl 2, how many grams of NaCl are produced? (No calculators!!) How many molecules of NaCl? Na + Cl 2  NaCl

Usually last questions

HOMEWORK #4   CST CH 3 booklet, standards 3a-3f;   pg #1-28