Chemistry Chapter 9 Notes #1

Review  Compounds Can all be represented by chemical formulas Can be  Ionic  Metallic  Covalent Compounds have different properties than the elements that make them up…

Review  Ionic Compounds Made up of a metal + nonmetal  (cation + anion) Attraction between positive and negative charge They come together to balance out the positive and negative charge Each chemical formula = formula unit

Covalent Compounds  Molecules When atoms are covalently bonded together  Chemical bond = Sharing of electrons  Nonmetal + nonmetal  The shared electrons are considered to be part of BOTH atoms outer energy levels

Forces involved  What keeps the atoms together in an ionic bond? Electrostatic attraction  What keeps the atoms together in a covalent bond? Attraction – nucleus to the electrons within each atom (and shared e-)  Repulsive forces: Between the 2 nuclei Btwn the 2 atoms e-  So the covalent bonds are weaker than ionic

Electron Dot Structures Electron Dot structures Chemical symbol + valence dots Paired V. unpaired (lone) electrons in electron dot structures…….

Bonds  When each atom gives one electron to be shared = single bond In total 2 electrons in the bond  Can be between 2 atoms or more, so that all atoms have 8 valence e-

Covalent Compounds-single bonds

Covalent Compounds  Multiple Covalent Bonds Double bond =  2 e- from each atom  (4 total) Triple Bond =  3 e- from each atom  (6 total)

Covalent Compounds

Examples O 2 N 2

Covalent Compounds  Naming  Use prefixes in front of the name of the first element Don’t use mono for element #1  Second element (the one to the farther right on the table) ends in -ide # atomsPrefix 1Mono- 2Di- 3Tri- 4Tetra- 5Penta- 6Hexa- 7Hepta- 8Octa- 9Nona- 10Deca-

Examples  As 2 O 5  SiO 4  P 4 S 3  Tetraphosphorous decoxide  Selenium dioxide  Phosphorous trichloride

Acids  Binary Acids H + one element Starts with “hydro” Name the “other” element, changing the ending to –ic Ex. HBr = Hydrobromic Acid

Acids  Oxyacids – H + oxyanion Ignore H (don’t name it) If suffix of the oxyanion ends in –ate, replace with –ic  Ex. HNO 3 = Nitric Acid If suffix of the oxyanion ends in –ite, replace with –ous  Ex. HNO 2 = Nitrous Acid

Examples  HCl  H 2 SO 4  H 2 SO 3  H 2 S  HydroFluoric Acid  Carbonic Acid  Bromic Acid