9.2 Periodicity of chemical properties of the elements in Period 3 Flashcards
Reaction of Na with oxygen
- burns in air with an orange flame to form white Na2O solid
Reaction of Mg with oxygen
- burns in air with an intense white flame to form white MgO solid
Reaction of Al with oxygen
- a layer of white Al2O3 solid forms very rapidly on exposure to air
Reaction of Si with oxygen
- reacts with oxygen on HEATING to form white SiO2 solid
Reaction of P with oxygen
- burns with a white flame in a plentiful supply of air to form white P4O10 solid (phosphorus pentoxide)
Reaction of S with oxygen
- burns with oxygen with a blue flame to form SO2, a dense, colourless gas with a choking pungent smell
- SO2 is further oxidised in the atmosphere to form SO3 (reversible reaction)
Reaction of Na with chlorine
- reduces chlorine on HEATING with a bright orange flame to form white NaCl solid
Reaction of Mg with chlorine
- reduces chlorine on HEATING with an intense white flame to form white MgCl2 solid
Reaction of Al with chlorine
- reduces chlorine on HEATING to form white AlCl3 solid
- AlCl3 undergoes dimerisation to form Al2Cl6 solid (to achieve stable octet)
Reaction of Si with chlorine
- reduces chlorine on HEATING to form colourless SiCl4 liquid
Reaction of P with chlorine
- reduces chlorine on HEATING to form PCl5, an off-white solid
Reaction of Na with water
- reacts with COLD WATER vigorously to colourless NaOH and hydrogen gas
Reaction of Mg with water
- reacts very slowly with COLD WATER to form a white precipitate of Mg(OH)2 and hydrogen gas
- reacts vigorously with STEAM and burns with a white flame to form white MgO solid and hydrogen gas
Reaction of Na2O (basic) with water
- reacts with water to form a strongly alkaline solution, NaOH, pH=13
- reacts with acids to form salt and water
- NaOH also reacts with acidic gases to form salt and water
Reaction of MgO (basic) with water
- reacts with water to form a weakly alkaline solution, Mg(OH)2, pH=9
* MgO does not react readily with water due to the high charge density of Mg2+ - reacts with acids to form salt and water
Reaction of Al2O3 (amphoteric) with water
- INSOLUBLE in water
- reacts with HOT acids to form salt and water
- reacts with alkalis to form salt
Reaction of SiO2 (acidic) with water
- INSOLUBLE in water
- reacts with HOT CONCENTRATED alkalis to form colourless silicate solution and water
- reacts with bases to form salt
Reaction of P4O10 (acidic) with water
- reacts with water to form a solution of phosphoric acid, H3PO4, pH=2
- reacts with bases to form salt and water
Reaction of SO2 (acidic) with water
- reacts with water to form sulfurous acid, H2SO3, pH=1
2. reacts with bases to form salt and water
Reaction of SO3 (acidic) with water
- reacts with water to form a strongly acidic solution, H2SO4 sulfuric acid, pH=1
- reacts with bases to form salt and water
Reaction of NaCl with water
- white solid dissolves in water to form a colourless neutral solution, pH=7
Reaction of MgCl2 with water
- dissolves in water to form a slightly acidic solution, pH=6.5
Reaction of AlCl3 with water
- hydrolyses in water to form an acidic solution, pH=3
- the complex ion [Al(H20)6] 3+ hydrolyses with water to produce H3O+ ions which make the solution acidic
Reaction of SiCl4 with water
- hydrolyses in water to form a strongly acidic solution
- effervescence, white fumes of HCl gas are produced
- white SiO2 solid forms
Reaction of PCl5 with water
- hydrolyses in water to form a strongly acidic solution, pH=1
- white fumes of HCl gas are produced
