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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). Group 5. Is at the centre of the periodic table Top of group, non-metals: Nitrogen and Phosphorus
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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
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 P block group V
Nitrogen Oxides 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
Nitrate(III) Nitrate(V) - - •• The charge is delocalised over the two N-O bonds, which are equivalent By using its lone pair to a dative covalent bond to an oxygen atom,the nitrogen increases its oxidation state to +5 Bonding in Nitrates P block group V
Nitrates P block group V