Properties of Oxides Across a Period (when added to water) basicacidic 8.6

Reactions of Oxides of Period 3 Oxides of metals react with water to form a base Na 2 O (s) + H 2 O (l)  2 NaOH (aq) Na 2 O (s) + H 2 O (l)  2 Na + (aq) + 2 OH 1- (aq) MgO (s) + H 2 O (l)  Mg(OH) 2 (aq) MgO (s) + H 2 O (l)  Mg 2+ (aq) + 2 OH 1- (aq) (NOTE: Mg(OH) 2 is not very soluble.) Oxides of metals can act as a base to neutralize an acid to form salt and water. Na 2 O (s) + HCl (aq)  2 Na + (aq) + 2 Cl 1- (aq) + H 2 O (l) MgO (s) + 2 HCl (aq)  Mg 2+ (aq) + 2 Cl 1- (aq) + H 2 O (l)

Reactions of Oxides of Period 3 Aluminum oxide is amphoteric (reacts with and dissolves in both acids and bases) Al 2 O 3 (s) + 6 H + (aq)  2 Al 3+ (aq) + 2 H 2 O (l) Al 2 O 3 (s) + 2 OH - (aq) + 3 H 2 O (l)  2 Al(OH) 3 (aq) Oxides of non metals react with water to form acids CO 2 (g) + H 2 O (l)  H + (aq) + 2 HCO 3 1- (aq) SiO 2 (s) + H 2 O (l)  not much of a reaction, however silicon dioxide will react as an acid to neutralize a base… SiO 2 (s) + 2 OH 1- (aq)  SiO 3 2- (s) + H 2 O (l) P 4 O 10 (s) + 6 H 2 O (l)  4 H + (aq) + 4 H 2 PO 4 1- (aq) SO 3 (s) + H 2 O (l)  H + (aq) + HSO 4 1- (aq)

Properties of Chlorides Across a Period (when added to water) neutralacidic 8.6 NaClMgCl 2 AlCl 3 (Al 2 Cl 6 (g) ) SiCl 4 PCl 3 PCl 5 Cl 2 Type of bondingmetallic giant covalent molecular covalent Structure crystalline solid (extensive 3D structure) solidgas Properties high melting points sublimes at 178°C to give vapor low melting and boiling points conduct electricity in molten and (aq) states molten chlorides do NOT conduct electricity (no ‘charged’ particles) aqueous chlorides DO conduct electricity Acid-Base Nature dissolve when added to water (neutral soln) react with water to form acidic soln

Reactions of Chlorides of Period 3 with water NaCl (s)  Na + (aq) + Cl - (aq) (No reaction, just dissolving) MgCl 2 (s)  Mg 2+ (aq) + 2 Cl - (aq) (No reaction, just dissolving)

Reactions of Chlorides of Period 3 AlCl 3 (s) + 3 H 2 O (l)  Al(OH) 3 (s) + 3 H + (aq) + 3 Cl - (aq) SiCl 4 (l) + 2 H 2 O (l)  SiO 2 (s) + 4 H + (aq) + 4 Cl - (aq) PCl 3 (l) + 3 H 2 O (l)  P(OH) 3 (aq) + 3 H + (aq) + 3 Cl - (aq) [Note: P(OH) 3 (aq) is also known as phosphoric(III) acid H 3 PO 3, a weak acid ] PCl 5 (s) + 4 H 2 O (l)  H 3 PO 4 (aq) + 5 H + (aq) + 5 Cl - (aq) [Note: H 3 PO 4 (aq) is known as phosphoric(V) acid, which is a strong acid ] Cl 2 (s) + H 2 O (l)  H + (aq) + Cl - (aq) + HOCl (aq) [Note: HOCl (aq) is known as chloric acid and is a weak acid ]

Homework:13.1 Read Section 13.1 on pp Do Exercise 13.1 on p 84 # 1-5 – due this Friday!