1. Periodic Trends in Period 3
Chlorides and Oxides
Bonding and Structure

2. Position of elements on the periodic table affects the type of bonding.

3. Period 3: Chlorides NaCl, MgCl2, AlCl3, SiCl4, PCl5
increase in the number of electrons available to form bonds.
increasing valence e-

4. Chlorides of Metals (NaCl, MgCl2)
ionic
high melting points
soluble in water
do not react with water
electrolytes (conduct electricity) as aqueous solutions or molten (liquid)
NaCl(aq)  Na+(aq) + Cl-(aq)

5. Electrolyte

6. Chlorides of Non-Metals (PCl5, PCl3)
molecular/covalent
weak van der Waal’s forces between molecules = low melting and boiling points
hydrolysis: to split by the action of water
PCl3(l) + 3H2O(l)  P(OH)3(aq) + 3H+(aq) + 3Cl-(aq)
non-metal/Cl bond replaced by a non-metal/O bond

7. non-metal chlorides (aq) conduct electricity (but not when molten)
Cl2: molecular/covalent, reacts with water in a hydrolysis reaction
Cl2(g) + H2O(l)  HOCl(aq) + HCl(aq)
Al: metal, but acts like a non-metal in bonds
because of it’s high charge, small size ion

8. Period 3 Oxides reducers oxidizers (donate e-) (accept e-)
Na2O, MgO, Al2O3, SiO2, P4O10, SO3, Cl2O7
P4O6 SO2 Cl2O basic acidic
reducers oxidizers
(donate e-) (accept e-)

9. Metals: Na, Mg ionic solids basic
react with water to make alkaline solution
Na2O(s) + H2O(l)  2Na+(aq) + 2OH-(aq)

10. Metalloids: Al “giant covalent lattices” high melting/boiling points
insoluble in water
Al2O3 is amphoteric (dissolves in acid or base)
Al2O3(s) + 6H+(aq)  2Al3+(aq) + 3H2O(l)
Al2O3(s) + 2OH-(aq)  3H2O(l) + 2Al(OH)4(aq)

11. Non-metals: Si, P, S, Cl molecular/covalent bonding
gases, liquids, solids with low melting points
non-metal oxides react with water to produce acids
P4O10(s) + 6H2O(l)  4H2PO4-(aq) + 4H+(aq)

12. Element Na Mg Al Si P S Cl
Bonding
Metallic
　Giant Covalent Lattice
Molecular/ Covalent
Chloride
Formula
NaCl
MgCl2
AlCl3
SiCl4
PCl5/PCl3
Cl2
Ionic
Molecular/covalent
Oxide
Na2O
MgO
Al2O3
SiO2
P4O10
SO3
Cl2O7
P4O6
SO2
Cl2O
Giant Covalent
Molecular/Covalent
Acid/Base
Soluble
Insoluble
Amphoteric
acidic
Properties
basic