Cheat Sheet: D and F - Block Elements | Chemistry Class 12 - NEET PDF Download

 Page 1


The d- an d f-Block Elements - CBSE
1. Introduction
The d- and f-block elements, known as tr ansition and inner tr ansition metals,
occup y the middle and bottom sections of the periodic table. Their unique prop-
erties arise from partially filled d or f orbitals.
2. Position in the Periodic T able
• d-Block (Groups 3–12): Inner d orbitals (3d, 4d, 5d, 6d) progressively filled;
spans four long periods.
• f-Block: 4f (lanthanoids, Ce–Lu) and 5f (actinoids, Th–Lr) orbitals filled;
placed separ ately at the bottom.
3. Tr ansition Metals (d-Block)
• Series: 3d (Sc–Zn), 4d (Y–Cd), 5d (La, Hf–Hg), 6d (A c, Rf–Cn).
• Definition (IUP A C): Metals with incomplete d subshell in neutr al atoms or
ions (except Z n, Cd, Hg with d
10
).
• Electronic Configur ation: (n-1)d
1--10
ns
1--2
; exceptions: Cr ([Ar]3d
5
4s
1
),
Cu ([Ar] 3d
10
4s
1
), Pd ([Kr]4d
10
).
T able: Electronic Configur ations (3d Series, Ground State)
Element Sc Ti V Cr Mn F e Co Ni Cu Zn
Z 21 22 23 24 25 26 27 28 29 30
4s 2 2 2 1 2 2 2 2 1 2
3d 1 2 3 5 5 6 7 8 10 10
4. Gener al Char acteristics of d-Block Elements
(a) Ph ysical Properties:
• Metallic: High tensile strength, ductility , malleability , thermal/electrical
conductivity (e xcept Zn, Cd, Hg, Mn).
• High melting/boiling points: Strong metallic bonding due to (n-1)d and ns
electrons; m axima at d
5
(e.g., V , Cr).
• Lattice structu res: hcp (Sc, Ti), bcc (V , Cr), ccp (Ni, Cu), or mixed (F e, Co).
• High enthalpies o f atomisation: Maxima mid-series (e.g., V: 515 kJ/mol); Zn
lowest (12 6 kJ/mol).
1
Page 2


The d- an d f-Block Elements - CBSE
1. Introduction
The d- and f-block elements, known as tr ansition and inner tr ansition metals,
occup y the middle and bottom sections of the periodic table. Their unique prop-
erties arise from partially filled d or f orbitals.
2. Position in the Periodic T able
• d-Block (Groups 3–12): Inner d orbitals (3d, 4d, 5d, 6d) progressively filled;
spans four long periods.
• f-Block: 4f (lanthanoids, Ce–Lu) and 5f (actinoids, Th–Lr) orbitals filled;
placed separ ately at the bottom.
3. Tr ansition Metals (d-Block)
• Series: 3d (Sc–Zn), 4d (Y–Cd), 5d (La, Hf–Hg), 6d (A c, Rf–Cn).
• Definition (IUP A C): Metals with incomplete d subshell in neutr al atoms or
ions (except Z n, Cd, Hg with d
10
).
• Electronic Configur ation: (n-1)d
1--10
ns
1--2
; exceptions: Cr ([Ar]3d
5
4s
1
),
Cu ([Ar] 3d
10
4s
1
), Pd ([Kr]4d
10
).
T able: Electronic Configur ations (3d Series, Ground State)
Element Sc Ti V Cr Mn F e Co Ni Cu Zn
Z 21 22 23 24 25 26 27 28 29 30
4s 2 2 2 1 2 2 2 2 1 2
3d 1 2 3 5 5 6 7 8 10 10
4. Gener al Char acteristics of d-Block Elements
(a) Ph ysical Properties:
• Metallic: High tensile strength, ductility , malleability , thermal/electrical
conductivity (e xcept Zn, Cd, Hg, Mn).
• High melting/boiling points: Strong metallic bonding due to (n-1)d and ns
electrons; m axima at d
5
(e.g., V , Cr).
• Lattice structu res: hcp (Sc, Ti), bcc (V , Cr), ccp (Ni, Cu), or mixed (F e, Co).
• High enthalpies o f atomisation: Maxima mid-series (e.g., V: 515 kJ/mol); Zn
lowest (12 6 kJ/mol).
1
(b) Atomic/Ionic Radii:
• Decrease across series: Increasing nuclear charge, poor d-electron shield-
ing.
• Lanthanoid contr action: 5d series r adii similar to 4d (e.g., Zr: 160 pm, Hf:
159 pm) due to 4 f filling.
(c) Ionisation Enthalpies:
• Increase slightly across 3d series: 4s electrons lost first, 3d shielding re-
duces nucle ar charge effect.
• Exceptions: Lower for Mn
+
(d
5
), F e
2+
(d
5
) due to stable half-filled configu-
r ations.
(d) Oxidation States:
• V ariable: Differ b y 1 (e.g., V: +2 to +5, Mn: +2 to +7); max at group number
up to Mn (+7).
• Common: +2 (except Sc); Sc only +3, Zn only +2.
• Stable high states : Oxides/fluorides (e.g., Mn
7+
in Mn
2
O
7
, Cr
6+
in CrO
3
).
(e) Standard Electrode Potentials:
• M
2+
/M : Less negative across series; Cu positive (+0.34 V) due to high?
i
H
2
.
• M
3+
/M
2+
: Mn
3+
(+1.57 V) and Co
3+
(+1.97 V) strong oxidants; Cr
2+
reducing.
(f ) Other Properties:
• Magnetic: Par amagnetic (unpaired d electrons); µ =
v
n(n+2) BM (n =
unpaired elec trons).
• Coloured Ions: d-d tr ansitions (e.g., Cu
2+
blue, Ni
2+
green); d
0
, d
10
colour-
less.
• Complexes: Small size, high charge, d orbitals form complexes (e.g., [Cu(NH
3
)
4
]
2+
).
• Catalytic: V ariable oxidation states (e.g., V
2
O
5
in Contact Process, F e in
Haber ’ s).
• Interstitial Compounds: Hard, high MP (e.g., TiC, F e
3
H).
• Allo ys: Similar r adii form hard allo ys (e.g., steel, br ass).
2
Page 3


The d- an d f-Block Elements - CBSE
1. Introduction
The d- and f-block elements, known as tr ansition and inner tr ansition metals,
occup y the middle and bottom sections of the periodic table. Their unique prop-
erties arise from partially filled d or f orbitals.
2. Position in the Periodic T able
• d-Block (Groups 3–12): Inner d orbitals (3d, 4d, 5d, 6d) progressively filled;
spans four long periods.
• f-Block: 4f (lanthanoids, Ce–Lu) and 5f (actinoids, Th–Lr) orbitals filled;
placed separ ately at the bottom.
3. Tr ansition Metals (d-Block)
• Series: 3d (Sc–Zn), 4d (Y–Cd), 5d (La, Hf–Hg), 6d (A c, Rf–Cn).
• Definition (IUP A C): Metals with incomplete d subshell in neutr al atoms or
ions (except Z n, Cd, Hg with d
10
).
• Electronic Configur ation: (n-1)d
1--10
ns
1--2
; exceptions: Cr ([Ar]3d
5
4s
1
),
Cu ([Ar] 3d
10
4s
1
), Pd ([Kr]4d
10
).
T able: Electronic Configur ations (3d Series, Ground State)
Element Sc Ti V Cr Mn F e Co Ni Cu Zn
Z 21 22 23 24 25 26 27 28 29 30
4s 2 2 2 1 2 2 2 2 1 2
3d 1 2 3 5 5 6 7 8 10 10
4. Gener al Char acteristics of d-Block Elements
(a) Ph ysical Properties:
• Metallic: High tensile strength, ductility , malleability , thermal/electrical
conductivity (e xcept Zn, Cd, Hg, Mn).
• High melting/boiling points: Strong metallic bonding due to (n-1)d and ns
electrons; m axima at d
5
(e.g., V , Cr).
• Lattice structu res: hcp (Sc, Ti), bcc (V , Cr), ccp (Ni, Cu), or mixed (F e, Co).
• High enthalpies o f atomisation: Maxima mid-series (e.g., V: 515 kJ/mol); Zn
lowest (12 6 kJ/mol).
1
(b) Atomic/Ionic Radii:
• Decrease across series: Increasing nuclear charge, poor d-electron shield-
ing.
• Lanthanoid contr action: 5d series r adii similar to 4d (e.g., Zr: 160 pm, Hf:
159 pm) due to 4 f filling.
(c) Ionisation Enthalpies:
• Increase slightly across 3d series: 4s electrons lost first, 3d shielding re-
duces nucle ar charge effect.
• Exceptions: Lower for Mn
+
(d
5
), F e
2+
(d
5
) due to stable half-filled configu-
r ations.
(d) Oxidation States:
• V ariable: Differ b y 1 (e.g., V: +2 to +5, Mn: +2 to +7); max at group number
up to Mn (+7).
• Common: +2 (except Sc); Sc only +3, Zn only +2.
• Stable high states : Oxides/fluorides (e.g., Mn
7+
in Mn
2
O
7
, Cr
6+
in CrO
3
).
(e) Standard Electrode Potentials:
• M
2+
/M : Less negative across series; Cu positive (+0.34 V) due to high?
i
H
2
.
• M
3+
/M
2+
: Mn
3+
(+1.57 V) and Co
3+
(+1.97 V) strong oxidants; Cr
2+
reducing.
(f ) Other Properties:
• Magnetic: Par amagnetic (unpaired d electrons); µ =
v
n(n+2) BM (n =
unpaired elec trons).
• Coloured Ions: d-d tr ansitions (e.g., Cu
2+
blue, Ni
2+
green); d
0
, d
10
colour-
less.
• Complexes: Small size, high charge, d orbitals form complexes (e.g., [Cu(NH
3
)
4
]
2+
).
• Catalytic: V ariable oxidation states (e.g., V
2
O
5
in Contact Process, F e in
Haber ’ s).
• Interstitial Compounds: Hard, high MP (e.g., TiC, F e
3
H).
• Allo ys: Similar r adii form hard allo ys (e.g., steel, br ass).
2
5. Important Compounds
(a) Potassium Dichromate (K
2
Cr
2
O
7
):
• Prepar ation: Chromite ore (F eCr
2
O
4
) fused with Na
2
CO
3
and O
2
, acidified
to Na
2
Cr
2
O
7
, treated with K Cl.
• Structure: CrO
2–
4
(tetr ahedr al), Cr
2
O
2–
7
(two tetr ahedr a, Cr–O–Cr 126°).
• Properties: Or ange crystals, strong ox idant in acidic solution:
Cr
2
O
2–
7
+
14
H
+
+
6
e
–
2
Cr
3+
+
7
H
2
O (E
?
=1.33 V)
Oxidises I
–
to I
2
, F e
2+
to F e
3+
, Sn
2+
to Sn
4+
.
• Uses: Leather industry , organ ic synthesis, volumetric analysis.
(b) Potassium Permanganate (KMnO
4
):
• Prepar ation: MnO
2
fused with K OH and O
2
or KNO
3
, forms K
2
MnO
4
, dis-
proportionates to MnO
–
4
.
• Structure: T etr ahedr al MnO
–
4
; diamagnetic (no unpaired electrons).
• Properties: Purple crystals, strong oxidant:
MnO
–
4
+
8
H
+
+
5
e
–
Mn
2+
+
4
H
2
O (E
?
=1.52 V)
A cidic: Oxidises F e
2+
, C
2
O
2–
4
, I
–
, NO
–
2
. Neutr al/alkaline: F orms MnO
2
.
• Uses: Analytical chemi stry , organic synthesis, bleaching textiles.
6. Inner Tr ansition Elements (f-Block)
• Series: Lanthanoids (Ce–Lu, 4f ), A ctinoids (Th–Lr , 5f ).
• Electronic Configur ation: Lanthanoids: [Xe]4f
1--14
5d
0--1
6s
2
; A ctinoids:
[Rn]5f
0--14
6d
0--1
7s
2
.
(a) Lanthanoids:
• Atomic/Ionic Radii: Decrease (lanthanoid contr action) due to poor 4f shield-
ing; affects 5d series.
• Oxidation States: +3 common; +2 (Eu, Yb), +4 (Ce, Tb) r are, due to stable
f
0
, f
7
, f
14
.
• Properties: Silvery , soft, reactive with water/acids; form Ln
2
O
3
, Ln(OH)
3
,
LnX
3
.
• Coloured I ons: f-f tr ansitions (e.g., Nd
3+
pink); La
3+
, Lu
3+
colourless.
• Uses: Mischmetall (95 % Ln) in allo ys, catalysts in petroleum cr acking.
3
Page 4


The d- an d f-Block Elements - CBSE
1. Introduction
The d- and f-block elements, known as tr ansition and inner tr ansition metals,
occup y the middle and bottom sections of the periodic table. Their unique prop-
erties arise from partially filled d or f orbitals.
2. Position in the Periodic T able
• d-Block (Groups 3–12): Inner d orbitals (3d, 4d, 5d, 6d) progressively filled;
spans four long periods.
• f-Block: 4f (lanthanoids, Ce–Lu) and 5f (actinoids, Th–Lr) orbitals filled;
placed separ ately at the bottom.
3. Tr ansition Metals (d-Block)
• Series: 3d (Sc–Zn), 4d (Y–Cd), 5d (La, Hf–Hg), 6d (A c, Rf–Cn).
• Definition (IUP A C): Metals with incomplete d subshell in neutr al atoms or
ions (except Z n, Cd, Hg with d
10
).
• Electronic Configur ation: (n-1)d
1--10
ns
1--2
; exceptions: Cr ([Ar]3d
5
4s
1
),
Cu ([Ar] 3d
10
4s
1
), Pd ([Kr]4d
10
).
T able: Electronic Configur ations (3d Series, Ground State)
Element Sc Ti V Cr Mn F e Co Ni Cu Zn
Z 21 22 23 24 25 26 27 28 29 30
4s 2 2 2 1 2 2 2 2 1 2
3d 1 2 3 5 5 6 7 8 10 10
4. Gener al Char acteristics of d-Block Elements
(a) Ph ysical Properties:
• Metallic: High tensile strength, ductility , malleability , thermal/electrical
conductivity (e xcept Zn, Cd, Hg, Mn).
• High melting/boiling points: Strong metallic bonding due to (n-1)d and ns
electrons; m axima at d
5
(e.g., V , Cr).
• Lattice structu res: hcp (Sc, Ti), bcc (V , Cr), ccp (Ni, Cu), or mixed (F e, Co).
• High enthalpies o f atomisation: Maxima mid-series (e.g., V: 515 kJ/mol); Zn
lowest (12 6 kJ/mol).
1
(b) Atomic/Ionic Radii:
• Decrease across series: Increasing nuclear charge, poor d-electron shield-
ing.
• Lanthanoid contr action: 5d series r adii similar to 4d (e.g., Zr: 160 pm, Hf:
159 pm) due to 4 f filling.
(c) Ionisation Enthalpies:
• Increase slightly across 3d series: 4s electrons lost first, 3d shielding re-
duces nucle ar charge effect.
• Exceptions: Lower for Mn
+
(d
5
), F e
2+
(d
5
) due to stable half-filled configu-
r ations.
(d) Oxidation States:
• V ariable: Differ b y 1 (e.g., V: +2 to +5, Mn: +2 to +7); max at group number
up to Mn (+7).
• Common: +2 (except Sc); Sc only +3, Zn only +2.
• Stable high states : Oxides/fluorides (e.g., Mn
7+
in Mn
2
O
7
, Cr
6+
in CrO
3
).
(e) Standard Electrode Potentials:
• M
2+
/M : Less negative across series; Cu positive (+0.34 V) due to high?
i
H
2
.
• M
3+
/M
2+
: Mn
3+
(+1.57 V) and Co
3+
(+1.97 V) strong oxidants; Cr
2+
reducing.
(f ) Other Properties:
• Magnetic: Par amagnetic (unpaired d electrons); µ =
v
n(n+2) BM (n =
unpaired elec trons).
• Coloured Ions: d-d tr ansitions (e.g., Cu
2+
blue, Ni
2+
green); d
0
, d
10
colour-
less.
• Complexes: Small size, high charge, d orbitals form complexes (e.g., [Cu(NH
3
)
4
]
2+
).
• Catalytic: V ariable oxidation states (e.g., V
2
O
5
in Contact Process, F e in
Haber ’ s).
• Interstitial Compounds: Hard, high MP (e.g., TiC, F e
3
H).
• Allo ys: Similar r adii form hard allo ys (e.g., steel, br ass).
2
5. Important Compounds
(a) Potassium Dichromate (K
2
Cr
2
O
7
):
• Prepar ation: Chromite ore (F eCr
2
O
4
) fused with Na
2
CO
3
and O
2
, acidified
to Na
2
Cr
2
O
7
, treated with K Cl.
• Structure: CrO
2–
4
(tetr ahedr al), Cr
2
O
2–
7
(two tetr ahedr a, Cr–O–Cr 126°).
• Properties: Or ange crystals, strong ox idant in acidic solution:
Cr
2
O
2–
7
+
14
H
+
+
6
e
–
2
Cr
3+
+
7
H
2
O (E
?
=1.33 V)
Oxidises I
–
to I
2
, F e
2+
to F e
3+
, Sn
2+
to Sn
4+
.
• Uses: Leather industry , organ ic synthesis, volumetric analysis.
(b) Potassium Permanganate (KMnO
4
):
• Prepar ation: MnO
2
fused with K OH and O
2
or KNO
3
, forms K
2
MnO
4
, dis-
proportionates to MnO
–
4
.
• Structure: T etr ahedr al MnO
–
4
; diamagnetic (no unpaired electrons).
• Properties: Purple crystals, strong oxidant:
MnO
–
4
+
8
H
+
+
5
e
–
Mn
2+
+
4
H
2
O (E
?
=1.52 V)
A cidic: Oxidises F e
2+
, C
2
O
2–
4
, I
–
, NO
–
2
. Neutr al/alkaline: F orms MnO
2
.
• Uses: Analytical chemi stry , organic synthesis, bleaching textiles.
6. Inner Tr ansition Elements (f-Block)
• Series: Lanthanoids (Ce–Lu, 4f ), A ctinoids (Th–Lr , 5f ).
• Electronic Configur ation: Lanthanoids: [Xe]4f
1--14
5d
0--1
6s
2
; A ctinoids:
[Rn]5f
0--14
6d
0--1
7s
2
.
(a) Lanthanoids:
• Atomic/Ionic Radii: Decrease (lanthanoid contr action) due to poor 4f shield-
ing; affects 5d series.
• Oxidation States: +3 common; +2 (Eu, Yb), +4 (Ce, Tb) r are, due to stable
f
0
, f
7
, f
14
.
• Properties: Silvery , soft, reactive with water/acids; form Ln
2
O
3
, Ln(OH)
3
,
LnX
3
.
• Coloured I ons: f-f tr ansitions (e.g., Nd
3+
pink); La
3+
, Lu
3+
colourless.
• Uses: Mischmetall (95 % Ln) in allo ys, catalysts in petroleum cr acking.
3
(b) A ctinoids:
• Atomic/Ionic Radii: A ctinoid contr action, greater than lanthanoid due to
poorer 5f shie lding.
• Oxidation States: +3 common; +4 to +7 in early actinoids (e.g., U: +6, Np:
+7).
• Properties: Radioactive, silvery , reactive with water/non-metals; complex
magnetic proper ties.
• Comparison with Lanthanoids: Greater oxidation state r ange, 5f elec-
trons more invol ved in bonding.
7. Applications
• d-Block: F e/steel in construction, TiO
2
as pigment, V
2
O
5
in H
2
SO
4
produc-
tion, Ni in h y drogenation.
• f-Block: Lanthanoids in allo ys/catalysts, actinoids (T h, U) in nuclear energy .
4