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Periodic Relationship among the Oxides of the Elements Li to Cl

Periodic Relationship among the Oxides of the Elements Li to Cl. Ch. 39 Periodicity in Nature of Bonding of Oxides (p.19). The oxides of Periods 2 and 3 elements can be grouped into 3 types according to the nature of their bonding:. 1. Ionic oxides ;

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Periodic Relationship among the Oxides of the Elements Li to Cl

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  1. Periodic Relationship among the Oxides of the Elements Li to Cl

  2. Ch. 39 Periodicity in Nature of Bonding of Oxides (p.19) The oxides of Periods 2 and 3 elements can be grouped into 3 types according to the nature of their bonding: 1. Ionic oxides; 2. Ionic oxides with high covalent character; 3. Covalent oxides

  3. Periodicity in nature of bonding in the oxides of Periods 2 and 3 elements

  4. Structure of Oxides: table 39-2 p. 20 Do Check Point 39-1 on p. 22

  5. Trend in Oxidation Number (p.22-29) • Table 6 (p.28) shows periodicity of oxidation state. • Maximum oxidation number of each element (apart from fluorine) is the same as the group number • NF5does not exist because nitrogen cannot expand its octet

  6. Trend in Property of Oxide (p.23) • Basic Oxides  Amphoteric Oxides  Acidic Oxides Ionic Basic Na2O Ionic with Covalent character Amphoteric Al2O3 Covalent Acidic CO2 SO2 NO2

  7. Ionic Oxides (p.23) React with water  hydroxide (All Group I and II oxide except BeO) Li2O(s) + H2O(l)  2LiOH(aq) Na2O(s) + H2O(l)  2NaOH(aq) Na2O2(s) + 2H2O(l)  2NaOH(aq) + H2O2(aq) MgO(s) + H2O(l)  Mg(OH)2(aq) MgO is only slightly soluble in water because of its high lattice energy.

  8. BeO(s) + 2OH–(aq) + H2O(l)  [Be(OH)4]2–(aq) beryllate ion Al2O3(s) + 2OH–(aq) + 3H2O(l)  2[Al(OH)4]–(aq) aluminate ion Ionic oxides with high covalent character BeO and Al2O3 are amphoteric, and react with both acids and bases. Both are insoluble in water. BeO(s) + 2H+(aq)  Be2+(aq) + H2O(l) Al2O3(s) + 6H+(aq)  2Al3+(aq) + 3H2O(l)

  9. :O-H H Covalent Oxides B2O3(s) + 3H2O(l)  2H3BO3(aq) boric(III) acid Mechanism of the Hydrolytic behaviour of covalent oxides: O=X+ [O-X-OH]- + H+

  10. CO2(g) + H2O(l) H2CO3(aq) carbonic acid Group IV Oxides Carbon monoxide is neutral and insoluble in water. SiO2(s)does not react with water. It is slightly acidic, and reacts with boiling alkalis to form silicates(IV) SiO2(s) + 2NaOH(aq)  Na2SiO3(aq) + H2O(l)

  11. Group V Oxides Dinitrogen oxide and nitrogen oxide are neutral and insoluble in water. N2O3(g) + H2O(l)  2HNO2(aq) 2NO2(g) + H2O(l)  HNO2(aq) + HNO3(aq) cold nitric(III) nitric(V) acid acid N2O4(g) + H2O(l)  HNO2(aq) + HNO3(aq)

  12. N2O5(s) + H2O(l)  2HNO3(aq) cold nitric(V) acid P4O6 reacts slowly 2P4O6(s) + 6H2O(l)  4H3PO3(aq) cold phosphoric(III) acid P4O10 reacts vigorously (why?) 2P4O10(s) + 6H2O(l)  4H3PO4(aq) warm phosphoric(V) acid

  13. SO2(g) + H2O(l) H2SO3(aq) sulphuric(IV) acid SO3(g) + H2O(l) H2SO4(aq) sulphuric(VI) acid Group VI Oxides Oxygen is neutral and very slightly soluble in water. Mechanism??

  14. - + O O O O O O Cl Cl Cl Cl O O O O O O O O Cl2O7(g)/(l) Cl2O7(s) Group VIIA Oxides • Oxygen difluoride is a colourless gas which hydrolyzes slowly to form oxygen and hydrogen fluoride • OF2(g) + H2O(l)  2HF(aq) + O2(g) Cl2O(g) + H2O(l)  2HOCl(aq) chloric(I) acid Cl2O7(g) + H2O(l)  2HClO4(aq) chloric(VII) acid (very strong acid)

  15. Ionic Oxides, Na2O Small O2- has a high charge density O2- H-O-H  2 OH- Amphoteric Oxides Polarizing cation accepts lone pair electrons from OH- in alkaline medium. Small anion donates electron pairs to H+ acidic medium Covalent Oxides d+ on the central atom  accepts lone pair electrons from water  releasing a H+  acidic Acid-Base properties of oxides

  16. Periodicity in Nature of Bonding of Simple Hydrides The hydrides of Period 2 and 3 elements can be grouped into 3 types according to the nature of their bonding: 1. Ionic hydrides; 2. Covalent hydrides with some ionic character; 3. Typical covalent hydrides; 4. Polar covalent hydrides

  17. The END

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