1. Nitrogen Family/Gp-15
Pnicogens/Inertness

2. Group Members N(7) [He]2s22p3 Non-Metal P(15)-[Ne]3s23p3 Non-Metal
As(33)-[Ar]3d104s24p Metalloid
Sb-(51) [Kr]4d105s25p Metalloid
Bi-(83) [Xe]4f145d106s26p Non Metal

4. Electron afinity :-
Amount of energy released when one electron is accepted by the atom. The electron afinity goes on decreasing down the group.
Electronegativity:-
The tendency of an element to attract a bonded pair of electron towards itself.
15th group elements are more electronegative than 14th group because they are smaller in size.
Electronegativity goes on decreasing down the group.

5. Metallic character:-
Metallic character goes on increasing down the group.
Non-metallic character :-
It goes on decreasing down the group.
NITROGEN & PHOSPHOROUS are non-metals.
ARSENIC & ANTIMONY are metalloids.
BISMITH is a metal.

6. Oxidation state :-
Common oxidation state shown by these are +3 & +5 , but as we go down the group the +3 state is predominant due to inert pair effect.
Inert pair effect :-
The lower oxidation state is preferred over higher oxidation state as we go down the group. This is due to reluctant of S electrons to contribute in the bond formation due to poor shielding effect of d orbitals.

7. NITROGEN shows a wide range of
oxidation state since it is a non metal.
OS MOLECULE
 NH3
 NH2 NH2
 NH2OH
 N2
 N2O
 NO
 HNO2
 NO2
 HNO3

8. CHEMICAL PROPERTIES Hydrides Halides Oxides Oxo-acids
Disproportanation reaction
Hydrides :-they are as follows
NH  Ammonia
PH  Phosphine
AsH3  Arsine
SbH3  Stibine
BiH3  Bismuthine

11. BASIC NATURE OF HYDRIDES; These hydrides are lewis bases.
Ammonia is most basic in nature because the lone pair of electron is localized due to smaller size .
As the size increases the lone pair of electron get scaterred and are not available.
NH3>PH3>AsH3>SbH3>BiH3
BOND ANGLE;
The bond angle decreases down the group.
107° ° ° ° °

12. REDUCING PROPERTY
Substance capable of giving H easily is called as reducing agent.
NH3<PH3<AsH3<SbH3<BiH3
BiH3 is very good reducing agent b’cause t is
Bond length between Bi-H is longer.

13. DISPROPORTANATION REACTION;
when reactant of one oxidation state can give product of two or more than two oxidation state.
3HNO2 HNO3+2NO+H2O ( In acidic medium)
4H3PO33H3PO4+PH3

14. HALIDES OF GROUP -15
N-forms NCL3,NF3.
It is pyramidal in shape & has sp3
hybridization.

15. Ncl5 does not exit b’cause no vacant no d orbital
Ncl5 does not exit b’cause no vacant no d orbital. Pcl3 is pyramidal with sp3 hybridisation. P=3s2 3p3

16. Pcl5 is triangular pyramidal with sp3 hybridization

18. Group-15 oxides;
nitrogen forms a large variety of oxides ;
N2O(NITROUS)
PREPARATION:
NH4NO3N2O+2H2O
NO(NITRIC OXIDE)
2FeSo4+2NaNo2 +3H2So4Fe2(So4)3+2NaHSo4+2H2O+2NO

19. N2O3(DINITROGEN TRIOXIDE)
2NO+N2O42N2O3
NO2(NITROGEN DIOXIDE)
2Pb(NO3)24NO2+2PbO2
N2O4(DINITROGEN TETRAOXIDE)
2NO2N2O4

20. PREPARATION METHODS (lab):-
Ammonium chloride & sodium nitrite when heated gives nitrogen.
NH4Cl + NaNO2  N2 + NaCl + 2H2O
Ammonium dichromate undergoes decomposition to give nitrogen
(NH4)2Cr2O7  N2 + Cr2O3 + 4H2O

21. PHYSICAL PROPERTIES:-
NITROGEN is colorless, odorless, tasteless & very inactive. This is because it is less reactive due to high bond dissociation energy.
CHEMICAL PROPERTIES:-
With metals it forms Nitrides
6Li +N2  2Li3N
6Na + N2  2Na3N
With non-metals
N2 + H2  2NH3
N2 + O2 2NO

22. Ammonia:- NH3. It is sp3 hybridized
USES OF NITROGEN:-
It is used in refrigerants.
Manufacturing of ammonia.
Nitrogen is used to fill up electric bulbs.
Ammonia:- NH3.
It is sp3 hybridized
It is pyramidal in shape , good lewis base because it has lone pair of electron.

24. Ammonia lab preparation:-
Ammonium chloride when treated with sodium hydroxide forms ammonia.
NH4Cl + NaOH  NH3 + NaCl +H2O
Ammonia can also be prepared from urea .
NH2CONH2 + 2H2O  (NH4)2CO3  2NH3 + CO2 + H2O
Ammonia can also be prepared by treating ammonium sulphate with calcium hydroxide.
(NH4)2SO4 + Ca(OH)2  CaSO4 + 2NH3 + 2H2O

25. USES OF AMMONIA:- Ammonia is used for preparing fertilizers.
& for preparing Nitric acid .
NITRIC ACID :-
N  +5 State
HNO3 is a oxo-acid or oxyacid .
HNO3 has a plannar structure.
It is a monoprotic acid , it releases only 1 H+ ions.

27. GROUP 15
QUESTION &ANSWER

28. Q1)WRITE THE STATE OF HYBRIDISATION OF N IN NO2?
ANS) SP2 HYBRIDISATION.
Q2) IN TRIMETHYLAMINE, ‘N’ IS PYRAMIDAL, IN N(SiH3)3, IT IS PLANAR, WHY?
ANS) IT IS DUE TO SP3 HYBRIDISATION AND ONE LONE PAIR IN N(CH3)3 WHEREAS IN SiH3, THERE IS SP2 HYBRIDISATION, LONE PAIR OF ELECTRTONE IS DONATED TO VACANT D-ORBITAL OF ‘Si’ WHEREAS ‘C’ DOESN’T HAVE D-ORBITAL.

29. Q3)WHAT IS HYBRIDISATION OF ‘’ IN SF6 &’P’ IN PCl5? GIVE THERE SHAPE
ANS) ‘S’ IN SF6 IN SP3D2 HYBRIDISED & OCTAHEDRAL SHAPED
‘P’ IN PCl5 IS SP3d HYBRIDISED AND TRIGONAL BIPYRAMIDAL Cl F Cl F F Cl p S Cl F F F Cl

30. Q4) WHY IS NITROGEN GAS WHEREAS PHOPHORUS SOLID?
ANS) N2 MOLECULES HAVE LESS VAN DER WALLS’ FORCE OF ATTRACTION WHEREAS P4 MOLECULES HAVE MORE VAR DER WALLS’ FORCE OF ATTRACTION.
Q5) MENTION THE CONDITION REQUIRED TO MAX. YIED OF NH3?
ANS) [1] MODERATE TEMP. = 700K
[2] HIGH PRESSURE = 20MPa
[3] IRON OXIDE + AL2O3 + K20 AS CATALYST

31. Q6) WHY DO NITROGEN SHOW ANOMALOUS BEHAVIOUR?
ANS) IT IS DUE TO
{1} SMALLEST ATOMIC SIZE
{2} HIGHEST ELECTRONAGTIVITY
{3} No d-ORBITALS
Q7) HOW DOES NH3 REACT WITH A SOLUTION OF Cu2+ ?
ANS)
Cu2+ (aq) + 4NH3(aq) [Cu(NH3)4]2+

32. Q8) WHY DOES NCl5 NOT EXIT?
ANS) IT IS BECAUSE ‘N’ DOES NOT HAVE D- ORBITALS.
Q9) WHY DOES NH3 ACT AS LEWIS BASE?
ANS)IT IS DUE TO PREESNCE OF LONE PAIR OF ELECTRONS ON N.
Q10) WHY BiH3, THE STRONGEST REDUCING AGENT ALL THE HYDRIDES OF GROUP 15?
ANS) IT IS BECAUSE IT HAS LOWEST BOND DISSOCIATION ENERGY DUE TO LONGEST BOND LENGTH.

33. Q11) DISCUSS THE PATTERN OF VARIATION IN THE OXIDATION STATE OF THE FOLLOWING: P TO Bi?
ANS) THE TENDENCY TO SHOW -3 OXIDATION STATE DECREASES DOWN THE GROUP DUE TO DECREASE IN ELECTRONEGTIVITY. THE TENDENCY TO SHOW +5 OXIDATION STATE DECREASE FROM P TO Bi WHEREAS TENDENCY TO SHOW +3 OXIDATION STATE INCREASES DUE TO INERT PAIR EFFECT.

34. Q12) THROUGH NITROGEN EXHIBITES +5 OXIDATION STATE,IT DOESN’T FROM PENTAHALIDE. GIVE REASON.
ANS) IT SHOW +5 OXIDATION STATE IN N2O5 INVOLVING ONE COORDINATE BOND. N WITH n=2,HAS s AND p ORBITALS ONLY. IT DOESN’T HAVE d-ORBITALS TO EXPAND ITS VALENCE SHELL. THAT IS WHY IT DOESN’T FORM PENTAHALIDE.

35. Q13) PH3 HAS LOWER B.P THAN NH3. WHY?
ANS) UNLIKE NH3,PH3 MOLECULES AREN’T ASSOCIATED THROUGH HYDROGEN BONDING IN LIQUID STATE. THAT IS WHY THE B.P. OF PH3 IS LOWER THAN NH3.
Q14) WHY IS N2 LESS REACTIVE AT ROOM TEMP. THAN P4?
ANS) BECAUSE OF STRONG P-P OVERLAP RESULTING INTO THE TRIPLE BOND, N=N HAVING HIGH BOND DISSOCIATION ENERGY. P4 HAS SINGLE BOND, LOW DISSOCIATION ENERGY

36. Thank You
Amit Sharma
PGT Chemistry