6.1.3 Melting Point Trend Flashcards
1
Q
Summary table of physical properties of period 3 oxides
A
2
Q
What do Na2O and MgO form when reacted with water?
A
- Purely ionic bonding
- Alkaline solution
- O2 becomes OH-
- O2- (aq) + H2O (l) → 2OH- (aq)
3
Q
What happens when P4O10 and SO2 and SO3 react with water?
A
- Purely covalent
- Acidic
- Oxide + water forms acid which donate H+ to water
4
Q
What happens when Al2O3 and SiO2 bond with water?
A
- Insoluble
- But with hot, concentrated alkaline solution, act as base and form a salt
- Al can react with acidic solutions to form salt + water
- Al exhibits amphoteric behavior, there is covalent character
5
Q
Metal oxides with water
A
- Form alkaline solutions
- Sodium more because it is more soluble in water
- O-2 ion is strong base and readily produces OH- ions when reacted with water
6
Q
Oxides in middle of periodic table with water
A
- Al2O3 has covalent character, ions held strongly in lattice despite being ionic
- So does not dissolve
- Si2O doesnt either
7
Q
Non-metal oxides with water
A
- P and S are simple covalent molecules
- So react with water to produce acidic solutions
8
Q
Oxides as acids and bases
A
9
Q
Graphic trend in melting point of period 3 oxides
A
10
Q
Why is the melting point of Al2O3 so high?
A
- Ionic and has covalent character
- So lots of energy required to overcome forces
