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
