Chapter 5 (CIC) and Chapter 2, 8, 4 (CTCS)

• Read in CTCS Chapter 2.6, 8.2-3, 4.1-2

• 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+ - 11 protons and 10 electrons

[He]2s22p6

• Cl- - 17 protons and 18 electrons[Ne]3s23p6

• 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 themFormula Name

CH3CO2-1 or C2H3O2

-1 Acetate anion

HCO3- Bicarbonate anion

CO32- Carbonate anion

OH- Hydroxide anion

NO3- Nitrate anion

SO42- Sulfate anion

PO43- Phosphate anion

NH4+ 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 K2CO3, Al(CH3CO2)3, and Mg(HCO3)2

Why isn’t Salt a Molecule?• Na(s) + 1/2Cl2(g) NaCl(s) ΔH = -410.9 kJ/mol

• Lattice Energy:

– Q is charge of ion– d is distance between them– k is 8.99 x 109 Jm/C2

• As E increases (bonds get stronger) the charges increase or the size of the ions decrease

1 2Q QE

dk

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 H2O• Why is salt soluble in water?NaCl(s) + H2O(l) Na(OH2)x

+(aq) + Cl(H2O)y-(aq)

• Polyatomics remain intact

• Solubility Rules (Table 4.1 pg 111)

Soluble Compounds Insoluble Compounds

NO3- S2-except Ca2+, Sr2+, Ba2+

C2H3O2- CO3

2- but not HCO3-

Halides except Ag+, Pb2+, Hg22+ PO4

3-

SO42- except Sr2+, Ba2+, Pb2+, Hg2

2+ OH-except Sr2+, Ba2+

Group I and NH4+

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 stalagtitesMCO3

+ H2O M(HCO3)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”