The P Block Nitrogen and Group 5 This PPT from internet, but the content is very relevant though with more detail than you need…for now (Kev) P block group V

Group 5 Is at the centre of the periodic table Top of group, non-metals: Nitrogen and Phosphorus Bottom of group, metalloids (metallic elements with non-metal character): Antimony and Bismuth P block group V

N P As Sb Bi Nitrogen [He] 2s22p3 Phosphorus [Ne] 3s23p3 Arsenic [Ar] 14.0 N Nitrogen [He] 2s22p3 7 31.0 P Phosphorus [Ne] 3s23p3 15 74.9 As Arsenic [Ar] 3d104s24p3 33 121.8 Sb Antimony [Kr] 4d105s25p3 51 209.0 Bi Bismuth [Xe] 4f145d106s26p3 83 P block group V

Group 5 Group 5 elements can form 3 covalent bonds Sharing the 3 unpaired electrons Gives compounds with oxidation state of +3 or –3 for group 5 element Each atom has a lone pair of electrons Enables atoms to form dative covalent bonds When they do this Group 5 elements can form some compounds with oxidation state of +5 for the Group 5 element P block group V

Nitrogen Very abundant element Very unreactive! N2 unreactive because of strong triple bond holding N’s together Bond enthalpy of N N is +945 kJ mol-1 (Bond enthalpy of N-N is +158 kJ mol-1) Hence most reaction of N2 have high EA and require high T and catalysts to make them occur Haber process- high T + Fe catalyst…. Lightning or >2000ºC to make N2 react with O2 P block group V

.. Ammonia Ammonia is nitrogen hydride, NH3 Lone pair not involved in bonding Dative covalent bonds (dcb’s) possible P block group V

Ammonia + NH3 is a base and forms dcb’s to H+ ions to give ammonium ions (NH4+) Remember once dcb’s formed theyre no different from cb’s! NH3 also forms dcb’s with TM ions and is a good ligand in complexes (see earlier!!) Note: dcb = dative covalent bond cb = covalent bond P block group V

Nitrogen Oxides Name / Formula Appearance Where it comes from Nitrogen monoxide NO Colourless gas, turns to brown NO2 in air Combustion processes Thunderstorms Formed in the soil by denitrifying bacteria P block group V

Nitrogen Oxides Name / Formula Appearance Where it comes from Nitrogen dioxide NO2 Brown gas (toxic) Cu + 4HNO3? From oxidation of NO in the atmosphere Dinitrogen oxide N2O Colourless gas Formed in the soil by denitrifying bacteria P block group V

Nitrates 2 Kinds of nitrate ions involved in the nitrogen cycle: Nitrate(III), NO2- Nitrate(V), NO3- Both are called nitrates, but distinguished by showing the Ox.State of N P block group V

The charge is delocalised over the two N-O bonds, which are equivalent Bonding in Nitrates The charge is delocalised over the two N-O bonds, which are equivalent Nitrate(III) - •• - By using its lone pair to a dative covalent bond to an oxygen atom,the nitrogen increases its oxidation state to +5 Nitrate(V) P block group V

Nitrates Name and Formula Common name Properties Nitrate(V) ion NO3- Oxidising agent Metal nitrate(V) compounds are very soluble in water Nitrate(III) ion NO2- Nitrite Can be reducing or oxidising agent Metal nitrate(III) compounds are soluble in water P block group V