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The p-Block Elements Class 11 Notes Chemistry

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General outer Electronic configuration : ns
2
np
1–6
.
Inert Pair Effect:
? Reluctance of ns
2
 electrons of valence shell to participate in bond formation
is termed as inert pair effect.
? It arises due to poor or insufficient shielding of ns
2
 electrons by intervening
d- or f-electrons & hence increases down the group.
Causes of Anomalous Behaviour of First Element in groups of p-Block:
(i) Very small size
(ii) Unavailability of vacant d-orbital
(iii) Tendency to form p
p
 –  p
p
 multiple bonds.
Group No-13 Elements: (B, Al, Ga, In, Tl, Nh)
? General Electronic Configuration: ns
2
 np
1
? Atomic radius: B < Ga < Al < In <TI
r
Ga
 < r
Al
 due to ineffective shielding of valence electrons by intervening 3d-
electrons in Ga.
? Ionization Enthalpies:        : B > Tl > Ga > Al > In
? Electronegativity: B > Tl > In > Ga > Al
? Oxidation States: B (+3), Al (+3), Ga (+3, +1), In (+3, +1), Tl (+1, +3)
Tl (+1) is more stable than Tl (+3) due to inert pair effect.
Page 2


General outer Electronic configuration : ns
2
np
1–6
.
Inert Pair Effect:
? Reluctance of ns
2
 electrons of valence shell to participate in bond formation
is termed as inert pair effect.
? It arises due to poor or insufficient shielding of ns
2
 electrons by intervening
d- or f-electrons & hence increases down the group.
Causes of Anomalous Behaviour of First Element in groups of p-Block:
(i) Very small size
(ii) Unavailability of vacant d-orbital
(iii) Tendency to form p
p
 –  p
p
 multiple bonds.
Group No-13 Elements: (B, Al, Ga, In, Tl, Nh)
? General Electronic Configuration: ns
2
 np
1
? Atomic radius: B < Ga < Al < In <TI
r
Ga
 < r
Al
 due to ineffective shielding of valence electrons by intervening 3d-
electrons in Ga.
? Ionization Enthalpies:        : B > Tl > Ga > Al > In
? Electronegativity: B > Tl > In > Ga > Al
? Oxidation States: B (+3), Al (+3), Ga (+3, +1), In (+3, +1), Tl (+1, +3)
Tl (+1) is more stable than Tl (+3) due to inert pair effect.
? Nature of Compounds: Compounds of group 13 elements are electron
deficient i.e. Lewis Acid and hence used as industrial catalyst e.g. BF
3
, AlCl
3
.
? Oxides:  B
2
O
3
 Al
2
O
3
, Ga
2
O
3
 ln
2
O
3
 Tl
2
O
Acidic Amphoteric Basic Strongly Basic
? Halides: MX
3
 type, Electron deficient (Lewis acid), AICI
3
 exist as dimer
? Borax: Na
2
B
4
O
7
.10H
2
O. On heating it form transparent glassy bead
consisting of NaBO
2
 + B
2
O
3
.
? Boric acid: H
3
BO
3
, It acts as a Lewis acid by accepting electron pair from
OH
–
 ions of water.
? Diborane: B
2
H
6
, Colourless & toxic gas, acts as Lewis acid due to having
electron deficient 3c-2e
–
 bonds. Obtained by treating BF
3
 with LiAIH
4
 or
NaH, Also obtained by treating NaBH
4
 with l
2
.
? Borazine: B
3
N
3
H
6
, It is isostructural with benzene and hence known as inor-
ganic benzene. Prepared by heating B
2
H
6
 withNH
3
Group -14 Elements: (C, Si, Ge, Sn, Pb,Fl)
? General Electronic Configuration: ns
2
 np
2
? Atomic radius: C < Si < Ge < Sn < Pb
? lonisation Enthalpy: LiH
x
 : C > Si > Ge > Sn < Pb
? Oxidation States: C (+4), Si (+4), Ge (+4, +2), Sn (+4, +2), Pb (+4, +2)
Pb (+2) is more stable than Pb (+4) due to inert pair effect.
? Oxides: Form di oxides (MO
2
) & mono oxides (MO).
PbO
2
 is powerfull oxidizing agent because Pb stabilizes in +2 oxidation state
due to inert pair effect. CO
2
 is gas while SiO
2
 is network solid because C has
ability to form p
p
 — p
p
 multiple bonds.
? Halides: Form tetra halides (MX
4
) & dihalides (MX
2
).
Tetra halides are more covalent due to greater polarizing power of cation.
CCI
4
 is not hydrolysed with water as C has no vacant d-orbital to accept
electron pair from water.
Page 3


General outer Electronic configuration : ns
2
np
1–6
.
Inert Pair Effect:
? Reluctance of ns
2
 electrons of valence shell to participate in bond formation
is termed as inert pair effect.
? It arises due to poor or insufficient shielding of ns
2
 electrons by intervening
d- or f-electrons & hence increases down the group.
Causes of Anomalous Behaviour of First Element in groups of p-Block:
(i) Very small size
(ii) Unavailability of vacant d-orbital
(iii) Tendency to form p
p
 –  p
p
 multiple bonds.
Group No-13 Elements: (B, Al, Ga, In, Tl, Nh)
? General Electronic Configuration: ns
2
 np
1
? Atomic radius: B < Ga < Al < In <TI
r
Ga
 < r
Al
 due to ineffective shielding of valence electrons by intervening 3d-
electrons in Ga.
? Ionization Enthalpies:        : B > Tl > Ga > Al > In
? Electronegativity: B > Tl > In > Ga > Al
? Oxidation States: B (+3), Al (+3), Ga (+3, +1), In (+3, +1), Tl (+1, +3)
Tl (+1) is more stable than Tl (+3) due to inert pair effect.
? Nature of Compounds: Compounds of group 13 elements are electron
deficient i.e. Lewis Acid and hence used as industrial catalyst e.g. BF
3
, AlCl
3
.
? Oxides:  B
2
O
3
 Al
2
O
3
, Ga
2
O
3
 ln
2
O
3
 Tl
2
O
Acidic Amphoteric Basic Strongly Basic
? Halides: MX
3
 type, Electron deficient (Lewis acid), AICI
3
 exist as dimer
? Borax: Na
2
B
4
O
7
.10H
2
O. On heating it form transparent glassy bead
consisting of NaBO
2
 + B
2
O
3
.
? Boric acid: H
3
BO
3
, It acts as a Lewis acid by accepting electron pair from
OH
–
 ions of water.
? Diborane: B
2
H
6
, Colourless & toxic gas, acts as Lewis acid due to having
electron deficient 3c-2e
–
 bonds. Obtained by treating BF
3
 with LiAIH
4
 or
NaH, Also obtained by treating NaBH
4
 with l
2
.
? Borazine: B
3
N
3
H
6
, It is isostructural with benzene and hence known as inor-
ganic benzene. Prepared by heating B
2
H
6
 withNH
3
Group -14 Elements: (C, Si, Ge, Sn, Pb,Fl)
? General Electronic Configuration: ns
2
 np
2
? Atomic radius: C < Si < Ge < Sn < Pb
? lonisation Enthalpy: LiH
x
 : C > Si > Ge > Sn < Pb
? Oxidation States: C (+4), Si (+4), Ge (+4, +2), Sn (+4, +2), Pb (+4, +2)
Pb (+2) is more stable than Pb (+4) due to inert pair effect.
? Oxides: Form di oxides (MO
2
) & mono oxides (MO).
PbO
2
 is powerfull oxidizing agent because Pb stabilizes in +2 oxidation state
due to inert pair effect. CO
2
 is gas while SiO
2
 is network solid because C has
ability to form p
p
 — p
p
 multiple bonds.
? Halides: Form tetra halides (MX
4
) & dihalides (MX
2
).
Tetra halides are more covalent due to greater polarizing power of cation.
CCI
4
 is not hydrolysed with water as C has no vacant d-orbital to accept
electron pair from water.
? Catenation: C >> Si > Ge ˜ Sn >> Pb
? Allotrops of carbon: Diamond (sp
3
), Graphite (sp
2
), Fullerenes (sp
2
)
? Silicones: Silicones are synthetic organosilicon compounds containing
R
2
SiO repeating units. Silicones are water repellent, heat resistant, chemi-
cally inert, electrical insulators, resistant to oxidation.
? Silicates: Silicates are compounds in which anions are derived from
Si–o–si– tetrahedral units.
? Zeolites: Zeolites are 3D silicates in which some of the Si atoms are replaced
by Al
3+
 ions and negative charge is balanced by cations such as Na
+
, K
+
,
Ca
2+
 etc.
? ZSM-5 is used in petrochemical industries to convert methanol into petrol.
Group - 15 Elements: (N, P, As, Sb, Bi, Mc)
? General Electronic Configuration: ns
2
 np
3
? Atomic radius: N < P < As < Sb < Bi
? lonisation Enthalpy: D
i
H
1
: N > P > As > Sb > Bi
? Oxidation States: N (+5, +3), P (+5,+3), As (+5, +3), Sb (+5,+3), Bi (+5,
+3) Bi (+3) is more stable than Bi (+5) due to inert pair effect.
? Oxides: Form trioxides (M
2
O
3
) & pentaoxides (M
2
O
5
).
? Halides: Form trihalides (MX
3
) & pentahalides (MX
5
).
Nitrogen does not form penta halides because it cannot extend its covalency
beyond four due to absence of vacant d-orbitals.
Pentahalides are more covalent than trihalides due to greater polarizing
power of cation.
? Hydrides: MH
3
 type, Lewis base, pyramidal structure
  NH
3
 > PH
3
 > AsH
3
 > SbH
3
 > BiH
3
 
(Basic character, Bond angle & Thermal Stability) 
  NH
3 
< PH
3 
< AsH
3 
< SbH
3 
< BiH
3
 
(Reducing Character) PH
3
< AsH
3
< NH
3
< SbH
3
< BiH
3
 (Boiling point)
Page 4


General outer Electronic configuration : ns
2
np
1–6
.
Inert Pair Effect:
? Reluctance of ns
2
 electrons of valence shell to participate in bond formation
is termed as inert pair effect.
? It arises due to poor or insufficient shielding of ns
2
 electrons by intervening
d- or f-electrons & hence increases down the group.
Causes of Anomalous Behaviour of First Element in groups of p-Block:
(i) Very small size
(ii) Unavailability of vacant d-orbital
(iii) Tendency to form p
p
 –  p
p
 multiple bonds.
Group No-13 Elements: (B, Al, Ga, In, Tl, Nh)
? General Electronic Configuration: ns
2
 np
1
? Atomic radius: B < Ga < Al < In <TI
r
Ga
 < r
Al
 due to ineffective shielding of valence electrons by intervening 3d-
electrons in Ga.
? Ionization Enthalpies:        : B > Tl > Ga > Al > In
? Electronegativity: B > Tl > In > Ga > Al
? Oxidation States: B (+3), Al (+3), Ga (+3, +1), In (+3, +1), Tl (+1, +3)
Tl (+1) is more stable than Tl (+3) due to inert pair effect.
? Nature of Compounds: Compounds of group 13 elements are electron
deficient i.e. Lewis Acid and hence used as industrial catalyst e.g. BF
3
, AlCl
3
.
? Oxides:  B
2
O
3
 Al
2
O
3
, Ga
2
O
3
 ln
2
O
3
 Tl
2
O
Acidic Amphoteric Basic Strongly Basic
? Halides: MX
3
 type, Electron deficient (Lewis acid), AICI
3
 exist as dimer
? Borax: Na
2
B
4
O
7
.10H
2
O. On heating it form transparent glassy bead
consisting of NaBO
2
 + B
2
O
3
.
? Boric acid: H
3
BO
3
, It acts as a Lewis acid by accepting electron pair from
OH
–
 ions of water.
? Diborane: B
2
H
6
, Colourless & toxic gas, acts as Lewis acid due to having
electron deficient 3c-2e
–
 bonds. Obtained by treating BF
3
 with LiAIH
4
 or
NaH, Also obtained by treating NaBH
4
 with l
2
.
? Borazine: B
3
N
3
H
6
, It is isostructural with benzene and hence known as inor-
ganic benzene. Prepared by heating B
2
H
6
 withNH
3
Group -14 Elements: (C, Si, Ge, Sn, Pb,Fl)
? General Electronic Configuration: ns
2
 np
2
? Atomic radius: C < Si < Ge < Sn < Pb
? lonisation Enthalpy: LiH
x
 : C > Si > Ge > Sn < Pb
? Oxidation States: C (+4), Si (+4), Ge (+4, +2), Sn (+4, +2), Pb (+4, +2)
Pb (+2) is more stable than Pb (+4) due to inert pair effect.
? Oxides: Form di oxides (MO
2
) & mono oxides (MO).
PbO
2
 is powerfull oxidizing agent because Pb stabilizes in +2 oxidation state
due to inert pair effect. CO
2
 is gas while SiO
2
 is network solid because C has
ability to form p
p
 — p
p
 multiple bonds.
? Halides: Form tetra halides (MX
4
) & dihalides (MX
2
).
Tetra halides are more covalent due to greater polarizing power of cation.
CCI
4
 is not hydrolysed with water as C has no vacant d-orbital to accept
electron pair from water.
? Catenation: C >> Si > Ge ˜ Sn >> Pb
? Allotrops of carbon: Diamond (sp
3
), Graphite (sp
2
), Fullerenes (sp
2
)
? Silicones: Silicones are synthetic organosilicon compounds containing
R
2
SiO repeating units. Silicones are water repellent, heat resistant, chemi-
cally inert, electrical insulators, resistant to oxidation.
? Silicates: Silicates are compounds in which anions are derived from
Si–o–si– tetrahedral units.
? Zeolites: Zeolites are 3D silicates in which some of the Si atoms are replaced
by Al
3+
 ions and negative charge is balanced by cations such as Na
+
, K
+
,
Ca
2+
 etc.
? ZSM-5 is used in petrochemical industries to convert methanol into petrol.
Group - 15 Elements: (N, P, As, Sb, Bi, Mc)
? General Electronic Configuration: ns
2
 np
3
? Atomic radius: N < P < As < Sb < Bi
? lonisation Enthalpy: D
i
H
1
: N > P > As > Sb > Bi
? Oxidation States: N (+5, +3), P (+5,+3), As (+5, +3), Sb (+5,+3), Bi (+5,
+3) Bi (+3) is more stable than Bi (+5) due to inert pair effect.
? Oxides: Form trioxides (M
2
O
3
) & pentaoxides (M
2
O
5
).
? Halides: Form trihalides (MX
3
) & pentahalides (MX
5
).
Nitrogen does not form penta halides because it cannot extend its covalency
beyond four due to absence of vacant d-orbitals.
Pentahalides are more covalent than trihalides due to greater polarizing
power of cation.
? Hydrides: MH
3
 type, Lewis base, pyramidal structure
  NH
3
 > PH
3
 > AsH
3
 > SbH
3
 > BiH
3
 
(Basic character, Bond angle & Thermal Stability) 
  NH
3 
< PH
3 
< AsH
3 
< SbH
3 
< BiH
3
 
(Reducing Character) PH
3
< AsH
3
< NH
3
< SbH
3
< BiH
3
 (Boiling point)
? Oxides of Nitrogen: Nitrogen having ability to form p
p
 – p
p
 multiple bonds
can form oxides in all oxidation states from +1 to +5 i.e. N
2
O, NO,N
2
O
3
,
NO
2
,N
2
O
4
 & N
2
O
5
? Dinitrogen (N
2
): Much less reactive due to high bond enthalpy of N =N.
Prepared by heating (NH
4
)
2
Cr
2
O
7
 or a solution of NH
4
Cl + NaNO
2
.
? Ammonia (NH
3
): Pungent & irritating smell gas. It is prepared on commer-
cial scale by Haber's process. NH
3
 acts as Lewis base /Ligand / complexing
agent due to the presence of electron pair on N atom.
? Nitric acid (HNO
3
): It is very powerfull oxidizing agent because it readi-
ly gives nascent oxygen both in concentrated or dilute form. Concentrated
HNO
3
 oxidizes non-metals to their oxoacids and metals to their nitrates.
? Allotropes of Phosphorous: White (Most reactive due to angular strain),
Red & Black phosphorous.
? Phosphine (PH
3
): Poisonous gas with rotten fish smell, it is prepared by
heating white phosphorous with concentrated. NaOH in inert atmosphere of
CO
2
. Phosphine can also be prepared by dropping H
2
O or HCI on Ca
3
P
2
.
? Phosphorous trichloride (PCl
3
): Colourless liquid, fumes in moisture due
to the formation of HCI.
? Phosphorous pentachloride (PCl
5
): In gaseous state it is covalent (trigonal
bipyramid) but in solid state it is ionic i.e. [PCl
4
]
+
[PCl
6
]
–
.
? Oxoacids of Phosphorous:
  (i)  Hypophosphorous acid (H
3
PO
2
): Monobasic, reducing
(ii) Phosphorous acid (H
3
PO
3
): Dibasic/reducing
(iii) Phosphoric acid (H
3
PO
4
): Tribasic, Non-reducing
(iv) Hypophosphoric acid (H
4
P
2
O
6
): Tetrabasic, non-reducing a          
(v) Pyrophosphoric acid (H
4
P
2
O
7
): Tetrabasic, non-reducing
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FAQs on The p-Block Elements Class 11 Notes Chemistry

1. What are p-block elements?
Ans. p-block elements are a group of elements in the periodic table that belong to groups 13-18. They are called p-block elements because their valence electrons are in the p orbital. These elements have diverse chemical properties and are found in various compounds and materials.
2. What are the properties of p-block elements?
Ans. p-block elements have several important properties. They can exhibit multiple oxidation states, form covalent bonds, and have a wide range of electronegativity values. They can also form compounds with different types of elements, including metals, nonmetals, and metalloids, due to their versatile nature.
3. How are p-block elements classified?
Ans. p-block elements are classified into three categories: metals, nonmetals, and metalloids. The metals in the p-block elements are found on the left side, the nonmetals are on the right side, and the metalloids are in between. This classification is based on their physical and chemical properties.
4. What are some important applications of p-block elements?
Ans. p-block elements have various applications in different fields. For example, carbon, a nonmetal in the p-block, is the basis of organic chemistry and forms the backbone of many important compounds. Boron, a metalloid, is used in the production of heat-resistant glass and ceramics. Nitrogen, a nonmetal, is used in the manufacture of fertilizers and explosives.
5. How do p-block elements contribute to the environment?
Ans. p-block elements play a crucial role in the environment. For instance, oxygen, a nonmetal in the p-block, is essential for the survival of living organisms as it is a key component of the air we breathe and is involved in various biological processes. Additionally, elements like phosphorus and sulfur, also found in the p-block, are vital nutrients for plants and are essential for the growth of crops.
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