3.2.4. Flashcards
Appearance and physical properties of sodium
metallic, shiny. conducts electricity (worst of metals)
Reaction of sodium with acid
Na + acid = H2 + salt
Reaction of sodium with cold water
Observation: floats on water, vigorous fizzing, melts due to exothermic reaction
Equation: 2Na + 2H2O = 2NaOH + H2
pH: 13-14
Reaction of sodium with oxygen
Observation: Bright yellow flame and white powder
Equation: 2Na + 1/2O2 = Na2O
Appearance and physical properties of magnesium
Metallic, shiny and conducts electricity (better than Na but not as good as Al)
The reaction of magnesium with cold water
Observation: very slow reaction
Equation: Mg + 2H2O = H2 + Mg(OH)2
pH: 10 (Mg(OH)2 is insoluble)
The reaction of magnesium with steam
Mg + H2O = MgO + H2
The reaction of magnesium with oxygen
Observation: White flame and white powder
Equation: 2Mg + O2 = 2MgO
Appearance and physical properties of aluminum
Metallic, shiny and the best electrical conductor of period 3
The reaction of aluminum with cold water
no reaction
Reaction of aluminium with oxygen
Observation: Bright flame and white powder
Equation: 4Al + 3O2 = 2Al2O3
Why is aluminum oxide considered unreactive even if the metal itself is considered reactive
Al2O3 coats the surface and is unreactive. If scratched off Al reacts with air.
Appearance and physical properties of silicon
Metalloid and a semiconductor
Reactions of silicon with oxygen
Heat strongly
Si + O2 = SiO2
(white powder)
Appearance and physical properties of phosphorus
Non-metal, low M.P. and B.P., does not conduct electricity
Red Phosphorus as a crystal structure
White phosphorus as P4
Reaction of phosphorus in excess oxygen
Red phosphorus needs to be heated
White phosphorus ignites spontaneously in air
Observation: forms white crystaline solid
Equation: 4P + 5O2 = P4O10
Reaction of phosphorus in limited oxygen
Observation: Phosphorus trioxide (colourless liquid)
Equation: 4P + 3O2 = P4O6
Appearance and physical properties of sulphur
Non-metal, low M.P. and B.P., does not conduct electricity
Reaction of sulphur with oxygen
Heat sulphur and lower into a jar of oxygen
Observation: colourless gas and some SO3
Equation: S + O2 = SO2
Structure and bonding of Na
Ionic lattice
Structure and bonding of Mg
Ionic lattice
Structure and bonding of Al
Ionic lattice with covalent character
Al3+ distorts O2- electron cloud
Structure and bonding of Si
giant covalent
Structure and bonding of P
simple covalent molecule
Structure and bonding of S
simple covalent molecule
