Period 3 revision sheet

Mathsandscience.net Period 3 elements and periodicity. Electronegativity increases ,Proton number increases (increase in nuclear charge),Same number of electron shells/levels ,to nucleus increases both react with water but Mg requires steam 2Na (s) + 2H2O (l) 2NaOH (aq) + H2 (g) Mg (s) + H2O (g) MgO (s) + H2 (g) Formation of the oxides 4Na(s) + O2(g)g 2Na2O(s) 4P(s) + 5O2(g)g P4O10 (s) 2Mg (s) + O2 (g)g2MgO (s) S(s) + O2(g) "SO2(g) s 4Al(s) + 3O2(g)g 2Al2O3 (s) Si(s) + O2(g)gSiO2 (s) Reactions of oxides with water 2Na2O + H2O g Na OH + H2 pH10-11 MgO + 2H2O g Mg(OH )2 + H2 pH 8 Al2O3 + H2O No reaction SiO2+ H2O No reaction P4O10 + 6H2O g 4H3PO4 pH2 SO2 + H2O g H2SO3 pH1 pH trend of the solutions formed goes from alkaline to acidic. Less electronegative sodium has a weak Na-O bond and the oxygen easily given up to react with H+ . A strong S-O bond keeps this together and more H+ is generated. The amphoteric aluminium oxide has a bonding which is both ionic and covalent in nature meaning it reacts with both acids and bases. Reaction with acids. Na2O + 2H Cl 2Na Cl + H2O MgO + 2 H Cl Mg Cl2 + H2O Al2O3 + 6 H Cl 2AlCl3 + 3H2O Al2O3 + 2Na OH + 3H2O 2NaAl(OH)4 SiO2 + 2NaOH Na2SO3 + H2O H3PO4+ NaOH NaH2PO4 + H2O (etc) H2SO4 + 2NaOH Na2SO4 + 2 H2O Copyright 2010 Tutoring for AS and A2 Mathsandscience.net