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

basic acidic

8.6

Reactions of Oxides of Period 3

Oxides of metals react with water to form a base

Na2O (s) + H2O (l) 2 NaOH (aq)

Na2O (s) + H2O (l) 2 Na+ (aq) + 2 OH1- (aq)

MgO (s) + H2O (l) Mg(OH)2 (aq)

MgO (s) + H2O (l) Mg2+ (aq) + 2 OH1- (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.

Na2O (s) + HCl (aq) 2 Na+ (aq) + 2 Cl1- (aq) + H2O (l)

MgO (s) + 2 HCl (aq) Mg2+ (aq) + 2 Cl1- (aq) + H2O (l)

Reactions of Oxides of Period 3

Aluminum oxide is amphoteric (reacts with and dissolves in both acids and bases)

Al2O3 (s) + 6 H+ (aq) 2 Al3+ (aq) + 2 H2O (l) Al2O3 (s) + 2 OH- (aq) + 3 H2O (l) 2 Al(OH)3 (aq)

Oxides of non metals react with water to form acids

CO2 (g) + H2O (l) H+ (aq) + 2 HCO31- (aq)

SiO2 (s) + H2O (l) not much of a reaction, however silicon dioxide will react as an acid to neutralize a base…

SiO2 (s) + 2 OH1- (aq) SiO3 2-

(s) + H2O (l)

P4O10 (s) + 6 H2O (l) 4 H+ (aq) + 4 H2PO41- (aq)

SO3 (s) + H2O (l) H+ (aq) + HSO41- (aq)

Properties of Chlorides Across a Period (when added to water)

neutral acidic

8.6

NaCl MgCl2AlCl3

(Al2Cl6 (g))SiCl4

PCl3PCl5

Cl2

Type of bonding metallicgiant

covalentmolecular covalent

Structurecrystalline solid(extensive 3D

structure)solid gas

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 Naturedissolve 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)

MgCl2 (s) Mg2+ (aq) + 2 Cl- (aq)

(No reaction, just dissolving)

Reactions of Chlorides of Period 3

AlCl3 (s) + 3 H2O (l) Al(OH)3 (s) + 3 H+ (aq) + 3 Cl- (aq)

SiCl4 (l) + 2 H2O (l) SiO2 (s) + 4 H+ (aq) + 4 Cl- (aq)

PCl3 (l) + 3 H2O (l) P(OH)3 (aq) + 3 H+ (aq) + 3 Cl- (aq)

[Note: P(OH)3 (aq) is also known as phosphoric(III) acid H3PO3, a weak acid ]

PCl5 (s) + 4 H2O (l) H3PO4 (aq) + 5 H+ (aq) + 5 Cl- (aq)

[Note: H3PO4 (aq) is known as phosphoric(V) acid, which is a strong acid ]

Cl2 (s) + H2O (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 82-84• Do Exercise 13.1 on p 84 # 1-5 – due this

Friday!