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P block group V 1

The P BlockThe P BlockNitrogen and Group 5

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P block group V 2

Group 5Group 5 Is at the centre of the periodictable

Top of group, non-metals: Nitrogen and Phosphorus

Bottom of group, metalloids

(metallic elements with non-metalcharacter): Antimony and Bismuth

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P block group V 3

14.0

N Nitrogen [He] 2s2

2p3

7

31.0

P Phosphorus [Ne] 3s23p315

74.9

As Arsenic [Ar] 3d104s24p333

121.8

SbA

ntimony [Kr]4d10

5s2

5p3

51

209.0

Bi Bismuth [Xe] 4f145d106s26p

383

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P block group V 4

Group 5Group 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 canform some compounds with oxidation state of+5 for the Group 5 element

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P block group V 5

NitrogenNitrogen Very abundant element Very unreactive! N2 unreactive because of strong triple

bond holding Ns 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 andrequire high T and catalysts to make themoccur Haber process- high T + Fe catalyst. Lightning or >2000C to make N2 react with O2

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P block group V 6

AmmoniaAmmonia Ammonia is nitrogenhydride, NH3

Lone pair notinvolved in bonding Dative covalent

bonds (dcbs)possible

N HH

H

..

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P block group V 7

AmmoniaAmmonia

NH3 is a base andforms dcbs to H+ ionsto give ammonium ions

(NH4+) Remember once dcbs

formed no different fromcbs!

NH3 also form

sdcb

swith TM ions and is a

good ligand in complexes(see earlier!!)

+

N HH

H

H

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P block group V 8

Nitrogen Oxides

Nitrogen Oxides

Name /Name /FormulaFormula

AppearanceAppearance Where it comesWhere it comesfromfrom

Nitrogenmonoxide

NO

Colourlessgas, turnsto brownNO2 in air

Combustionprocesses

Thunderstorms

Formed in thesoilby denitrifying

bacteria

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P block group V 9

Nitrogen Oxides

Nitrogen Oxides

Name /Name /FormulaFormula

AppearanceAppearance Where it comesWhere it comesfromfrom

Nitrogendioxide

NO2

Brown gas(toxic)

From oxidation ofNO in theatmosphere

Dinitrogenoxide

N2O

Colourle

ssgas

Formed in thesoilby denitrifying

bacteria

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P block group V 10

Nitrates

Nitrates

2 Kinds of nitrate ions involved inthe nitrogen cycle: Nitrate(III), NO2

-

Nitrate(V), NO3-

Both are called nitrates, but

distinguished by showing OS of N

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P block group V 11

Bonding in NitratesBonding in Nitrates

O

O

NO

-

By using its lone pair to

a dative covalent bondto an oxygen atom,thenitrogen increases itsoxidation state to +5

Nitrate(V)

The charge is

delocalised over thetwo N-O bonds, which

are equivalent

Nitrate(III)

-

N OO

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P block group V 12

NitratesNitratesName andFormula

Commonlycalled

Properties

Nitrate(V) ion

NO3-

Nitrate Oxidising agent

Metal nitrate(V)compounds are verysoluble in water

Nitrate(III) ion

NO2-Nitrite Can be reducing or

oxidising agent Metal nitrate(III)compounds aresoluble in water