1. 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

2. 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

3. 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

4. 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

5. 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

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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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