Chapter 5 (CIC) and Chapter 2, 8, 4 (CTCS) Read in CTCS Chapter 2.6, 8.2-3, Problems in CTCS: 2.31, 33, 35, 37, and 8.7, 9, 11, 13, 15, 17, 21, 23, 25, 27, and 4.1, 3, 5, 9, 11, 13, 15

Electrolytes Why is it bad to drop the radio in the bathtub? Electrolyte – a solution or compound in a solution that conducts electricity Nonelectrolyte – a solution or compound in a solution that doesn’t conduct electricity Ion – an electrically charged atom Cation – a positively charged ion (atom that has lost electrons) Anion – a negatively charged atom (atom that has gained electrons)

Ionic “Bond” What’s wrong with Na-Cl? Why do substances gain or lose e - ? Na protons and 10 electrons [He]2s 2 2p 6 Cl protons and 18 electrons [Ne]3s 2 3p 6 Ionic bonds occur when a metal and nonmetal interact –The nonmetal gives the anion –The metal gives the cation Electronegativity difference of 2 gives an ionic bond

Predicting Charges (Tables 2.4 and 2.5) Why did sodium only lose 1 electron? Why did chlorine only gain 1 electron? Q: Determine the number of electrons lost for the following elements: Li, Mg, Ti, Al Q: Determine the number of electrons gained for the following elements: F, O, P, As

Transition Metals (Table 2.4) Write the electron configurations for Fe, Cu, Cr, Zn, and Pb. Q: What would you expect for cation charges on these elements?

Polyatomic Ions Some ions have covalent bonds within themselves and do not break apart. Memorize them FormulaName CH 3 CO 2 -1 or C 2 H 3 O 2 -1 Acetate anion HCO 3 - Bicarbonate anion CO 3 2- Carbonate anion OH - Hydroxide anion NO 3 - Nitrate anion SO 4 2- Sulfate anion PO 4 3- Phosphate anion NH 4 + Ammonium cation

Deriving Formulas of Ionic Compounds Since compounds are neutral, cation and anion charges must balance Q: Write formulae of potassium oxide, ammonium sulfate and calcium phosphate Q: Write names for K 2 CO 3, Al(CH 3 CO 2 ) 3, and Mg(HCO 3 ) 2

Why isn’t Salt a Molecule? Na (s) + 1 / 2 Cl 2 (g)  NaCl (s) ΔH = kJ/mol Lattice Energy: –Q is charge of ion –d is distance between them –k is 8.99 x 10 9 Jm/C 2 As E increases (bonds get stronger) the charges increase or the size of the ions decrease

Size of Ions Electrons take up space and nuclei don’t Predict the relative sizes of the following species: F -, Ne, and Na + Isoelectronic species – those species with the same number of electrons Predict the relative sizes of F -, Cl -, and Br -

Solubility in H 2 O Why is salt soluble in water? NaCl (s) + H 2 O (l)  Na(OH 2 ) x + (aq) + Cl(H 2 O) y - (aq) Polyatomics remain intact Solubility Rules (Table 4.1 pg 111) Soluble CompoundsInsoluble Compounds NO 3 - S 2- except Ca 2+, Sr 2+, Ba 2+ C2H3O2-C2H3O2- CO 3 2- but not HCO 3 - Halides except Ag +, Pb 2+, Hg 2 2+ PO 4 3- SO 4 2- except Sr 2+, Ba 2+, Pb 2+, Hg 2 2+ OH - except Sr 2+, Ba 2+ Group I and NH 4 +

Double Displacement or Metathesis Reactions Write a molecular, ionic and net ionic equations between sodium carbonate and calcium nitrate. What are the spectator ions?

Environmental Consequences NaCl is in oceans and this water expensive to purify Fertilizers contain nitrates Most metals exist as insoluble oxides and sulfides As water runs through mines, it slowly leaches out metals and releases them to freshwater Stalagmites and stalagtites MCO 3 + H 2 O M(HCO 3 ) 2 (aq)

Covalent Compounds Covalent compounds usually consist of nonmetallic elements Why does sugar dissolve? Like dissolves like Water is about the only liquid material that has very polar bonds How well did water and cyclohexane mix? Ionic solvents and “Green Chemistry”