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Chemistry of Nonmetals

Chemistry of Nonmetals. OXIDATION-REDUCTION REACTIONS. A redox reaction involves the transfer of electrons between reactants Electrons gained by one species must equal electrons lost by another Both oxidation and reduction must occur simultaneously. Oxidation: removal of electrons

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Chemistry of Nonmetals

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  1. Chemistry of Nonmetals Dr.Riham Hazzaa

  2. OXIDATION-REDUCTION REACTIONS • A redox reaction involves the transfer of electrons between reactants • Electrons gained by one species must equal electrons lost by another • Both oxidation and reduction must occur simultaneously. • Oxidation:removal of electrons • Reduction:gain of electrons 2 Dr.RihamHazzaa

  3. oxidising and reducing agents • An oxidizing agentis an element which causes oxidation (and is reduced as a result) by removing electrons from another species. oxidizing agent is the electron acceptor • A reducing agentis an element which causes reduction (and is oxidized as a result) by giving electrons to another species. reducing agentis the electron donor. Na(s) + Cl (g) → NaCl(s) Dr.RihamHazzaa

  4. The main group metals are oxidized in all of their chemical reactions. These metals are oxidized when they react with nonmetal elements. Dr.RihamHazzaa

  5. Nonmetals can undergo both oxidation and reduction. • Phosphorus, is oxidized when it reacts with oxygen to form P4O10. • it is reduced when it reacts with calcium to form calcium phosphide. Dr.RihamHazzaa

  6. Phosphorus (EN = 2.19) is less electronegative than oxygen (EN = 3.44). When these elements react, the electrons are drawn toward the more electronegative oxygen atoms. Phosphorus is therefore oxidized in this reaction, and oxygen is reduced. • Calcium (EN = 1.00), on the other hand, is significantly less electronegative than phosphorus (EN = 2.19). When these elements react, the electrons are drawn toward the more electronegative phosphorus atoms. As a result, calcium is oxidized and phosphorus is reduced. Dr.RihamHazzaa

  7. The behavior of the nonmetals • Nonmetals tend to oxidize metals. • Nonmetals with relatively large electronegativities (such as oxygen and chlorine) oxidize substances with which they react. • Nonmetals with relatively small electronegativities (such as carbon and hydrogen) can reduce other substances. Dr.RihamHazzaa

  8. Hydrogen • Compounds of hydrogen are frequently called hydrides, even though the name hydride describes compounds that contain an H- ion. Dr.RihamHazzaa

  9. Because hydrogen forms compounds with oxidation numbers of both +1 and -1, many periodic tables include this element in both Group IA (with Li, Na, K, Rb, Cs, and Fr) and Group VIIA (with F, Cl, Br, I). • The first ionization energyof hydrogen (1312 kJ/mol), is halfway between the elements with the largest (2372 kJ/mol) and smallest (376 kJ/mol) ionization energies. • Hydrogen has an electronegativity (EN = 2.20) halfway between the extremes of the most electronegative (EN = 3.98) and least electronegative (EN = 0.7) elements. Dr.RihamHazzaa

  10. Hydrogen is oxidized by elements that are more electronegative to form compounds in which it has an oxidation number of +1. • Hydrogen is reduced by elements that are less electronegative to form compounds in which its oxidation number is -1. Dr.RihamHazzaa

  11. Formation of Hydrogen • By reacting an active metal with water. • By reacting a less active metal with a strong acid. Dr.RihamHazzaa

  12. By reacting an ionic metal hydride with water • By decomposing water into its elements with an electric current. Dr.RihamHazzaa

  13. The Chemistry of Nitrogen (GroupV) • A neutral nitrogen atom contains five valence electrons: 2s2 2p3. • Because the covalent radius of a nitrogen atom is relatively small (only 0.070 nm), nitrogen atoms come close enough together to form very strong bonds. • The strength of the nitrogen-nitrogen triple bond makes the N2 molecule very unreactive. Dr.RihamHazzaa

  14. The Synthesis of Ammonia NH3Haber process • The Haber process, a mixture of N2 and H2 gas at 200 to 300 atm and 400 to 600oC is passed over a catalystof finely divided iron metal. • Two-thirds of the ammonia used for fertilizers is converted into solids such as ammonium nitrate, NH4NO3; ammonium phosphate, (NH4)3PO4; ammonium sulfate, (NH4)2SO4; and urea, H2NCONH2. The other third is applied directly to the soil as anhydrous ammonia. Dr.RihamHazzaa

  15. The Synthesis of Nitric Acid Ostwald process Dr.RihamHazzaa

  16. The Nitrogen Oxides • Dinitrogen oxide, N2Owhich is also known as nitrous oxide, can be prepared by carefully decomposing ammonium nitrate. Dr.RihamHazzaa

  17. Nitrogen oxide, or nitric oxide, Nitrogen oxide NO can be prepared in the laboratory by reacting copper metal with dilute nitric acid. Dr.RihamHazzaa

  18. Nitrogen dioxide NO2 NO reacts rapidly with O2to form nitrogen dioxide (once known as nitrogen peroxide), which is a dark brown gas at room temperature. It can also be made by reacting copper metal withconcentrated nitric acid, Dr.RihamHazzaa

  19. Dinitrogen pentoxide By carefully removing water from concentrated nitric acid at low temperatures with a dehydrating agent we can form dinitrogen pentoxide. Dr.RihamHazzaa

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