Yb²⁺ - 4f¹⁴ - no unpaired electrons - diamagnetic

As we move from La to Lu, their metallic behaviour because almost similar to that of aluminium.

MnO^-₄ + 8H⁺ + 5e^- → Mn²⁺ + 4H₂O

+5           +6           +7
VO₂⁺ < Cr₂O₇^2- < MnO₄^-
Greater the oxidation state, higher is the oxidising power.

Cr ⇒ [Ar]3d⁵4s¹

Lr Z = 103, is the last element of actinoid series. Its electronic configuration is [Rn]⁸⁶ 5f¹⁴6d¹7S² the possible oxidation state shown by it is +3.

(i) HCl cannot be used for making the medium acidic since it reacts with KMnO₄ as follows.
2MnO₄^- + 10 Cl^- + 16H⁺ ⟶ 2Mn²⁺ + 5Cl₂+ 8H₂O
(ii) HNO₃ also cannot be used since it is good oxidising agent and reacts with reducing agents in the reaction.
(iii) However, H₂SO₄ is found to be most suitable since it does not react with potassium permanganate.

Potassium permanganate is a strong oxidising agent, its oxidising action differs in different reaction medium.
In neutral medium:
In neutral medium, it is reduced to MnO₂
MnO₄^- + 2H₂O + 3e^- ⟶ MnO₂ + 4OH^-
(i) It oxidises H₂S to sulphur
2MnO₄^- + 3H₂S ⟶ 2MnO₂ + 3S + 2OH^- + 2H₂O
(ii) It oxidises thiosulphate into sulphate
8MnO₄^- + 3S₂O₃^-2 + H₂O ⟶ 6SO₄^-2 + 8MnO₂ + 2OH^-

Potassium permanganate is prepared from pyrolusite (MnO₂) ore. The preparation involves the following steps
(i) Conversion of MnO₂ to potassium manganate: Powdered ore is fused with KOH in the presence of air or oxidising agents like KNO₃ or KCIO₃. A green coloured potassium manganate is formed.

(ii) Oxidation of potassium manganate to potassium permanganate: Potassium manganate thus obtained can be oxidised in two ways, either by chemical oxidation or electrolytic oxidation.

(i) When potassium dichromate is heated with any chloride salt in the presence of Conc. H₂SO₄, orange red vapours of chromyl chloride (CrO₂CI₂) is evolved.
(ii) This reaction is used to confirm the presence of chloride ion in inorganic qualitative analysis

(iii) The chromyl chloride vapours are dissolved in sodium hydroxide solution and then acidified with acetic acid and treated with lead acetate. A yellow precipitate of lead chromate is obtained

(i) They are hard and show electrical land thermal conductivity.
(ii) They have high melting points higher than those of pure metals.
(iii) Transition metal hydrides are used as powerful reducing agents.
(iv) Metallic carbides are chemically inert

i) Cr² + 2e^- ⟶ Cr
ii) Mn²⁺ + 2e^- ⟶ Mn
iii) Fe²⁺ + 2e^- ⟶ Fe
iv) CO²⁺ + 2e^- ⟶ Co

(i) The highest oxidation state in oxides and fluorides is due to small size and high electro negativity of F and O.
(ii) Many Cu⁺ compounds are unstable in aqueous solution and undergo disproportionation.
2Cu⁺ ⟶ Cu²⁺+ Cu
This suggest that in aqueous solution Cu+_(aq), converts into Cu²⁺_(aq) which is due to much more negative Δ_hyd H^- of Cu²⁺_(aq) than Cu⁺, which compensates more for the second ionisation enthalpy of Cu.

(i) Cobalt (III) ion has greater tendency to form complexes than cobalt (II) ion. Therefore, Co (II) ion being stable in aqueous solution, changes to Co (III) ion in the presence of complexing reagents and get oxidised.
(ii) Ions of transition metals with d¹ configuration tend to lose one electron to acquire d⁰ configuration that is quite stable. Therefore, such ions (with d¹) undergo either oxidation or disproportionation, hence unstable.

(i) Cr₂O₇^2- + 2OH^- ⟶ 2CrO₄^2- + H₂O
(ii) MnO₄^- + 4H⁺ + 3e^- ⟶ MnO₂ + 2H₂O

Cr²⁺ is stronger reducing agent than Fe²⁺. The standard electrode potential (E⁰) of Cr²⁺ is -0.91 V and that of Fe²⁺ is only -0.44 V.
If the standard electrode potential of a metal is large and negative is a powerful reducing agent, because it loses electrons easily.
Hence Cr²⁺ is stronger reducing agent.

La(OH)₃ is more basic than Lu(OH)₃. Due to lanthanide contraction, the size of Ln³⁺ ions decreases regularly with increase in atomic number. According to Fajan's rule, decrease in size of Ln³⁺ ions decreases the basic character between Ln³⁺ and OH^- ion in Ln(OH)₃. So La(OH)₃ is more basic than Lu(OH)₃.

(i) The actual position of Lanthanides in the periodic table is at group number 3 and period number 6. However, in the sixth period after lanthanum, the electrons are preferentially filled in inner 4f sub shell and these fourteen elements following lanthanum show similar chemical properties.
(ii) Similarly the fourteen elements following actinium resemble in their physical and chemical properties. Hence they are placed separately bottom of the modern periodic table.

IUPAC defines transition metal as an element whose atom has an incomplete d-sub shell or which can give rise to cations with an incomplete d-sub shell. They occupy the central position of the periodic table, between s and p-block elements.
Examples: Fe, Cu, Ag, Au

(i) According to Hume-Rothery rule to, form a substitute alloy the difference between the atomic radii of solvent and solute is less than 15%.
(ii) Both the solvent and solute must have the same crystal structure and valence and their electro negativity difference must be close to zero.

(i) An alloy is formed by blending a metal with one or more other elements. The elements may be metals or non-metals or both.
(ii) The bulk metal is named as solvent, and the other elements in smaller portions are called solute.
(iii) The alloys so formed are hard and often have high melting points.
(iv) Example: Ferrous alloys, gold - copper alloy, chrome alloys etc.

CrO < Cr₂O₃ < CrO₃
∴ Higher the oxidation state, more will be the acidic character.

Fe³⁺ has the electronic configuration
[Ar] 4s⁰ 3d⁵
It is 5 unpaired electron
μ = \(\sqrt{n(n+2)}\)
= \(\sqrt{5(5+2)}\) = \(\sqrt{35}\) = 5.9 BM

+3

Cu, Ag and Au which have been used in making of coins in ancient times are called coinage metals

(i) Transition metals have number of unpaired electron. They are involved in metallic bonding. Hence they show high melting point.
(ii) As we move from left to right along the transition metal series melting point first increases reach a maximum value and then decreases as the d-electrons pair up and become less available for bonding.

a. 3MnO₄^2- + 4H⁺ ⟶  2MnO₄^- + MnO₂ + 2H₂O
(Manganate ion) (Permanganate ion)  Manganese dioxide
b. C₆H₅CH₃ \(\overset { acidified }{ \underset { KMnO_{ 4 } }{ \longrightarrow } } \) C₆H₅COOH
 Toluene                         Benzoic Acid
c. 2MnO₄^- + 10Fe²⁺+16H⁺ \(\underrightarrow { { 8H }^{ + } } \)  2Mn²⁺+ 10Fe³⁺  + 8H₂O
d. 2KMnO₄ \(\overset { \triangle }{ \underset { Red\ hot }{ \longrightarrow } } \) K₂MnO₄ + MnO₂ + O₂
(Potassium Permanganate)    (Potassium Manganate)
e. Cr₂O₇^2- + 6I^- + 14H⁺ \(\underrightarrow { { (O) }}\) 2Cr³⁺ + 3I₂ + 7H₂O
                 (Iodide ion)                        Iodine
f. Na₂Cr₂O₇ + 2KCl ⟶ K₂Cr₂O₇ + 2NaCl
(Sodium dichromate)    (Potassium dichromate)

In Gd⁺³ there are 64 electrons. Hence electronic configuration will be [Xe]4f⁷ 5d¹ 6s². Hence no electrons are there in outer d - orbital. Due to this it is colourless.

(i) It oxidises ferrous salts to ferric salts.
 Cr₂O₇^2- + 6Fe²⁺+ 14H⁺ ⟶ 2Cr³⁺ + 6Fe³⁺ + 7H₂O
(ii) It oxidises iodide ions to iodine
Cr₂O₇^2- + 6I^-+ 14H⁺ ⟶ 2Cr³⁺ + 3I₂ + 7H₂O
(iii) It oxidises sulphide ion to sulphur
Cr₂O₇^2- + 3S^2-+ 14H⁺ ⟶ 2Cr³⁺ + 3S + 7H₂O
(iv) It oxidises sulphur dioxide to sulphate ion
Cr₂O₇^2- + 3SO₂+ 2H⁺ ⟶ 2Cr³⁺ + 3SO₄^2- + H₂O
(v) It oxidises stannous salts to stannic salt
 Cr₂O₇^2- + 3Sn²⁺ + 14H⁺ ⟶ 2Cr³⁺ + 3Sn⁴⁺ + 7H₂O
(vi) It oxidises alcohols to acids
2K₂Cr₂O₇ + 8H₂SO₄ + 3CH₃CH₂OH ⟶ 2K₂SO₄ +2Cr₂(SO₄)₃+ 3CH₃COOH + 11H₂O
(vii) It oxidises oxalic acid to CO2
2MnO₄^- + 5(COO)^2- + 6H⁺ ⟶ 2Mn²⁺+ 10CO₂ + 8H₂O
(viii) It oxidises iodide ions to iodine
2MnO4^- + 10I^- + 16H⁺ ⟶ 2Mn²⁺+ 5I₂+ 8H₂O
(ix) It oxidises sulphide ion to sulphur
2MnO₄^- + 5S^2-+ 16H⁺ ⟶ 2Mn²⁺+ 5S + 8H₂O
(x) It oxidises nitrites to nitrates
 2MnO₄^- + 5NO^2- + 6H⁺ ⟶ 2Mn²⁺+ 5NO₃^- + 3H₂O
(xi) It oxidises alcohols to aldehydes.
 2KMnO₄ + 3H₂SO₄ + 5CH₃CH₂OH ⟶ 2K₂SO₄ + 2MnSO₄ + 5CH₃CHO + 8H₂O
(xii) It oxidises sulphite to sulphate
2MnO₄^- + 5SO₃^2- + 6H⁺ ⟶ 2Mn²⁺ + 5SO₄^2- + 3H₂O

On the basis of magnetic properties, materials can be broadly classified as
(a) paramagnetic materials
(b) diamagnetic materials, besides these there are ferromagnetic and antiferromagnetic materials
(i) Materials with no elementary magnetic dipoles are diamagnetic, in other words a species with all paired electrons exhibits diamagnetism.
(ii) This kind of materials are repelled by the magnetic field because the presence of external magnetic field, a magnetic induction is introduced to the material which generates weak magnetic field that oppose the applied field
(iii) Paramagnetic solids having unpaired electrons possess magnetic dipoles which are isolated from one another.
(iv) In the absence of external magnetic field, the dipoles are arranged at random and hence the solid shows no net magnetism.
(v) But in the presence of magnetic field, the dipoles are aligned parallel to the direction of the applied field and therefore, they are attracted by an external magnetic field.
(vi) Ferromagnetic materials have domain structure and in each domain the magnetic dipoles are arranged.
(vii) But the spin dipoles of the adjacent domains are randomly oriented.
(viii) Some transition elements or ions with unpaired d electrons show ferromagnetism.

(i) It is generally expected a steady decrease in atomic radius along a period as the nuclear charge increases and the extra electrons are added to the same sub shell.
(ii) But for the 3d transition elements, the expected decrease in atomic radius is observed from Sc to V, thereafter up to Cu the atomic radius nearly remains the same.
(iii) As we move from Sc to Zn in 3d series the extra electrons are added to the 3d orbitals, the added 3d electrons only partially shield the increased nuclear charge and hence the effective nuclear charge increases slightly.
(iv) However, the extra electrons added to the 3d sub shell strongly repel the 4s electrons and these two forces are operated in opposite direction and as they tend to balance each other, it leads to constancy in atomic radii.
(v) At the end of the series, d - orbitals of Zinc contain 10 electrons in which the repulsive interaction between the electrons is more than the effective nuclear charge and hence, the orbitals slightly expand and atomic radius slightly increases.

The heavier transition elements belong to fourth (4d), fifth (Sd) and sixth (6d) transition series. Their properties are expected to be different form the elements belonging to the first (3d) series due to the following reasons.
(i) Atomic radii: Size of the transition elements 94d and Sd series are larger than those of the corresponding elements of the first transition series though those of 4d and Sd series are very close to each other.
(ii) Ionisation enthalpy of Sd series are higher than the corresponding elements of 3d and 4d series.
(iii) Atomisation enthalpy of 4d and Sd series are higher than the corresponding elements of the first series.
(iv) Melting and boiling points of heavier transition elements are greater than those of the first transition series due to stronger intermetallic bonding.
(v) The elements of the first transition series generally form low or high spin complexes, depending upon the higher of ligand field. However, the heavier transition elements form low spin complexes irrespective of the strength of the ligand filed.