JEE-d-and-f-block-Notes-_Final_compressed (1).pdf

Welcome to The d and f-Block Elements Coinage Metals (Cu, Ag, Au) Some ancient metal artifacts Copper, iron used to make weapons. “Dancing Girl” Made up of bronze metal used in Harappan civilization. These f-block elements are used in nuclear power plants. d-Block elements 3d series 4d series 5d ser...

Welcome to The d and f-Block Elements Coinage Metals (Cu, Ag, Au) Some ancient metal artifacts Copper, iron used to make weapons. “Dancing Girl” Made up of bronze metal used in Harappan civilization. These f-block elements are used in nuclear power plants. d-Block elements 3d series 4d series 5d series 6d series Pneumonic for d-Series Sachin Yes Larry Tendulkar Zebras Have fun Very Never but Travelling Crazy Most World and Man Technicians Reach Free Run Out Coaching to Rhymes Ireland and Nitin’s Purely sweet Please Cou And Ask Zin Cute Her f-Block elements Lanthanoids Actinoids d-Block Elements d-Block & f-block elements are known as transition and inner transition elements, respectively Generally, d-block elements are called transition elements Because their chemical properties are transitional between those of s- & p-block elements Known as transition metals Metals that have incomplete d subshell either in neutral atom or in their ions. Transition Elements Incomplete d subshell Fe : [Ar] Neutral Fe3+ Ion 3d6 4s2 3d5 4s0 : [Ar] Incomplete d subshell Inner Transition Elements f-Block elements are called inner transition elements Because their valence shell electrons lie in anti-penultimate energy level Example: Cerium (58) [Xe] 4f1 5d1 6s2 Non-transition d-Block Elements Zn (30) Zn2+ : [Ar] Cd (48) Cd2+ 3d10 4s0 : [Kr] 4d10 5s2 Zn, Cd, Hg of group 12 have full d10 configuration in their ground state as well as in their common oxidation states. : [Kr] 4d10 5s0 Hg (80) Hg2+ : [Ar] 3d10 4s2 : [Xe] 4f14 5d10 6s2 : [Xe] 4f14 5d10 6s0 Known as non-transition metals Transition d-Block Elements Silver is a transition element as it has incomplete d-orbital in its +2 oxidation state. Ag : [Kr] (41) Neutral Ag+ Ion 5s1 4d10 5s0 4d9 5s0 : [Kr] Ion Ag2+ 4d10 : [Kr] Incomplete in ionic state Position in the periodic table Transition elements Electronic configuration General properties Position of d-Block elements Electronic Configuration of d-Block Elements General configuration Last electron enters in the d-orbital Example (n-1)d1-10 ns1-2 Inner d-orbital Sc(21) 1s2 2s2 2p6 3s2 3p6 3d1 4s2 Co(27) 1s2 2s2 2p6 3s2 3p6 3d7 4s2 Electrons filling in 3d elements For 3d-series elements, electrons enters in 3d orbitals which is occupied generally after 4s orbital. Examples The electronic configuration has several exceptions because of very little difference in energy of (n-1)d and ns electrons. This can be reflected in electronic configuration of Cr (half filled) and Cu (fully filled) in 3d series. Cr(24) [Ar] 3d4 4s2 ❌ Ag(47) Cr(24) [Kr] [Ar] 4d 3d94 5s 4s2 ❌ Cr(24) [Ar] 3d5 4s1 ✔ Ag(47) Cr(24) 5 4s [Kr] 5s11 [Ar] 4d 3d10 ✔ Mo(42) [Kr] 4d4 5s2 ❌ Cu(29) [Ar] 3d9 4s2 ❌ Mo(42) Cr(24) [Kr] 3d 4d5 4s 5s1 [Ar] ✔ Cu(29) Cr(24) 5 4s [Ar] 4s11 [Ar] 3d 3d10 ✔ Examples Au(79) Cr(24) 14 5d 9 6s 4 4s 2 2 [Xe] 4f3d [Ar] ❌ Au(79) Cr(24) 10 16s1 5 4s [Xe] 4f14 [Ar] 3d5d ✔ Pd(46) [Kr] 4d8 5s2 ❌ Pd(46) Cr(24) 5 4s [Kr] 5s10 [Ar] 4d 3d10 ✔ Pt(78) [Xe] 4f14 5d8 6s2 ❌ Pt(78) Cr(24) 14 5d 9 6s 5 4s 1 1 [Xe] [Ar]4f3d ✔ Transition elements exhibit certain characteristic properties due to partially filled d-orbitals. Physical properties General properties Atomic properties Chemical properties Physical Properties All the transition elements display typical metallic properties High tensile strength High thermal and electrical conductivity Malleability Ductility Metallic lustre Hard and less volatile High melting and boiling points High tensile strength High electrical conductivity High thermal conductivity Malleability: Metals are highly malleable Metallic lustre: Metals are lusturous in nature Ductility: They are ductile and can be drawn into very thin wire Volatility: Metals are non-volatile in nature High boiling point Metals generally have high melting and boiling points High melting point Melting Point of Transition Elements Melting point of transition metal is high because of the involvement of greater number of electrons from (n-1)d in addition to the ns electrons in the interatomic metallic bonding. Melting Point of Transition Elements General rule Greater the number of unpaired electrons Higher will be the melting point In any row, 3d metals rise to a maximum at d5 Then, fall regularly as the atomic number increases Except for anomalous values of Mn and Tc Boiling Point of Transition Elements Transition elements have high boiling point due to high enthalpy of atomisation Enthalpy of Atomisation It is the enthalpy change on breaking one mole of bonds completely to obtain atoms in the gaseous phase. A2(g) 2A(g) Transition elements exhibit higher enthalpies of atomization due to high effective nuclear charge and large number of valence electrons. Form very strong metallic bonds. Arise due to unpaired electrons in the (n−1)d subshell. Boiling Point of Transition Elements General rule Greater the number of valence electrons Stronger is the resultant bonding Higher will be the boiling point. Boiling Point of Transition Elements 900 5d Series 800 4d Series ∆aH°/kJ mol-1 700 3d Series 600 500 400 300 200 100 Atomic number The maxima at about the middle of each series indicate that one unpaired electron per d orbital is particularly favourable for strong interatomic interaction. Boiling Point of Transition Elements 900 5d Series 800 4d Series ∆aH°/kJ mol-1 700 3d Series 600 500 400 300 200 100 Atomic number Boiling point of transition elements increases down the group. Boiling Point of Transition Elements Zero unpaired electrons Zn, Cd and Hg have low boiling point Zn Cd Weak metallic bonding Hg Lowest boiling and melting point Atomic radii and ionic radii Atomic properties Ionisation enthalpy Atomic Radii – 3d Series Due to poor shielding by d electrons, attraction increases more than repulsion Decreases gradually Sc > Ti > V > Cr > Mn ≈ Fe ≈ ≈ Co Nearly constant Repulsion almost balances out attraction Ni < Cu < Zn Increases Repulsion dominates attraction No. of (n-1)d electrons are very high Atomic Radii of Transition Elements New electron Left to right Attractive force e– e– Repulsive force + + Nuclear charge increases Attraction on outermost e- increases e– Increased nuclear charge electron in (n-1)d subshell Repulsion between electrons increases Atomic Radii of 3d, 4d and 5d Series Due to lanthanoid contraction 17 16 15 14 Radius/mm 19 18 Radius of 4d series is similar to radius of 5d series The filling of 4f before 5d orbital results in a regular decrease in atomic radii. 13 12 Sc Ti V Cr Mn Fe Co Ni Cu Zn Y Zr Nb Mo Tc Ru Rh Pd Ag Cd La Hf Ta W Re Os Ir Pt Au Hg The imperfect shielding of one electron by another in the same set of orbitals. Lanthanoid Contraction(Effect on Radii) Down the group Titanium (Ti) 4s2 3d2 147 pm Zirconium (Zr) 5s2 4d2 160 pm Hafnium (Hf) 4f14 6s2 5d2 159 pm Ti < Zr ≈ Hf Lanthanoid Contraction Reason 1 Shielding power of orbitals s>p>d>f Size decreases Nuclear attraction on outermost e− increases Lanthanoid Contraction Reason 2 Drastic increment in charge Titanium (Ti, 22) +18 increase in positive charge Increase in attraction Zirconium (Zr, 40) +32 increase in positive charge Hafnium (Hf, 72) Decrease in radii Lanthanoid Contraction Lanthanoid contraction essentially compensates for the expected increase in atomic size with increasing atomic number. Due to lanthanoid contraction, 4d and 5d elements have very similar physical and chemical properties. Due to decrease in radii and increase in atomic mass, density of transition elements is generally high. Density increases down the group Density increases from Sc to Cu along the period Trends in Ionisation Enthalpy Reason In general, from left to right ionization enthalpy increases Gradually. Due to an increase in nuclear charge Accompanied by the filling of the inner d-orbitals Ionisation enthalpy increases Ionisation Enthalpy Values For 3d Series 3d series I.E1 (kJmol-1) I.E2 (kJmol-1) I.E3 (kJmol-1) Sc 631 1235 2393 Ti 656 1309 2657 V 650 1414 2833 Cr 653 1592 2990 Mn 717 1509 3260 Fe 762 1561 2962 Co 758 1644 3243 Ni 736 1752 3402 Cu 745 1958 3556 Zn 906 1734 3837 Ionisation Enthalpy Zinc have significantly higher ionisation enthalpy than copper rZn I.E.Zn Due to completely filled d and s electrons in Zn, its first ionisation energy is more than Cu. 3d10 4s2 Fully filled > > rCu I.E.Cu First ionisation enthalpy 3d10 4s1 More stable High I.E. Chemical Properties Oxidation state Formation of complex compounds Standard electrode potential and reactivity Catalytic properties Magnetic properties Formation of interstitial compounds Colour Alloy formation Oxidation State of Transition Elements Due to incomplete filling of d-orbitals Mn2+ Mn6+ Transition elements show a great variety of oxidation states Manganese in different oxidation states Mn7+ Oxidation States of 3d Series Elements Oxidation states form regular pyramid Sc Ti V Cr Mn Fe Co Ni Cu Zn +1 +2 +2 +2 +2 +2 +2 +2 +2 +2 +3 +3 +3 +3 +3 +3 +3 +3 +4 +4 +4 +4 +4 +4 +4 +5 +5 +5 +6 +6 +6 +7 Oxidation State of 3d Transition Elements Sc3+ Common oxidation states Ti4+ V5+ Cr6+ Mn7+ d0 configuration Ti(IV) is more stable than Ti(III) or Ti(II) Ti2+ [Ar]3d2 4s0 Ti3+ [Ar]3d1 4s0 Ti4+ [Ar]3d0 4s0 Noble gas configuration Inert gas configuration Stable More stable Oxidation State of 3d Transition Elements Common oxidation states Mn2+(25) Zn2+ 3d10 4s0 3d5 4s0 Fe3+(26) Fully filled Half-filled orbital Stable More stable Oxidation State of 3d Transition Elements Requires high energy for removing electron Sc Sc+ : [Ar] 3d1 4s2 3d1 4s1 3d1 4s0 : [Ar] Sc2+ : [Ar] Oxidation State Stability - Down the Group Inert pair effect p-block Lower oxidation states are favoured by heavier elements Higher oxidation states are favoured by the heavier elements d-block Easier to remove valence electrons Oxidation State Stability - Down the Group Example Stability order Mo (VI) & W (VI) MoO3 and WO3 are not oxidising agents > Cr (VI) Dichromate ion 2– (Cr2O7 ) in acidic medium is a strong oxidising agent Inert pair effect p-block Oxidation state normally differ by unit of 2. Oxidation state normally differ by unity d-block Successive removal of electrons from d-orbital Oxidation State in d-block Elements Fe and Ni in Fe(CO)5 and Ni(CO)4 have zero oxidation states despite the d block elements favouring higher oxidation states Low oxidation state is favoured by metals when a complex compound has ligands Which are not just strong σ-donors but also π-acceptors like in Ni(CO)4 and Fe(CO)5, etc. Halides of 3d metals X :F→I XI : F → Br XII : F, Cl XIII: Cl → I Oxidation Number Group 3 4 5 +6 6 7 8 9 10 11 12 CrF6 +5 VF5 CrF5 +4 TiX4 VX4I CrX4 MnF4 +3 TiX3 VX3 CrX3 MnF3 FeX3I CoF3 +2 TiX2III VX2 CrX2 MnX2 FeX2 CoX2 NiX2 CuX2II ZnX2 +1 CuXIII Stability of Higher Oxidation States Fluorine stabilizes the highest oxidation state Stability through Example: CoF3 Higher lattice energy Example: VF5, CrF6 Higher bond enthalpy (higher covalent compound) Instability of CuII Iodides Cu2+ oxidises I – to I2 2Cu2+ + 4I – Cu2I2 (s) + I2 Oxides of 3d Metals * : Mixed oxides Oxidation number Group 3 4 5 6 +7 7 8 9 10 11 12 NiO CuO ZnO Mn2O7 +6 CrO3 +5 V2O5 +4 TiO2 V2O4 CrO2 MnO2 +3 Sc2O3 Ti2O3 V2O3 Cr2O3 Mn2O3 Fe2O3 Mn3O4* Fe3O*4 Co3O*4 +2 +1 TiO VO (CrO) MnO FeO CoO Cu2O Oxides of 3d Metals The ability of oxygen to stabilise these high oxidation states exceeds that of fluorine. MnF4 Highest Mn fluoride Mn2O7 Highest Mn oxide Oxides are more stable than halides due to ability of oxygen to form multiple bonds with metals. Reactivity of Transition Metals Transition metals vary widely in their chemical reactivity. The study of standard electrode potential is important to understand the Reactivity of transition elements Stability of various oxidation states Standard electrode potentials are measurements of the equilibrium potentials. Mn+ + ne– M, EM0n+/M Standard reduction potential Trends in standard electrode potentials M2+ M 0 (EM2+/M) M3+ M2+ (EM0 3+/M2+ ) Sublimation enthalpy(+ve) Cu shows positive standard electrode potential Enthalpy of atomisation & ionisation energies Cu (s) Cu (g); △sH High + The high energy required to transform Cu (s) to Cu2+ (g) Cu (g) Cu2+ (g); △iH Ionisation enthalpy (I.E.1 + I.E.2), +ve Not balanced by its hydration energy Cu2+ (g) Cu2+ (aq); △HydH Low Hydration enthalpy(-ve) Result Inability to liberate H2 from acid Only oxidising acids (HNO3, hot conc. H2SO4) react with Cu to liberate NO2 and SO2 and oxidise Cu to Cu2+ Cu (s) + 2HCl (aq) ❌ CuCl2 (aq) + H2 (g) Whereas, Zn (s) + 2HCl (aq) ZnCl2 (aq) + H2 (g) Reaction of metals with HCl Iron Nails Reaction of metals with HCl Nickel Balls Copper Spring Reaction of Cu with hot and conc. H2SO4 1 3 Cu + 2H2SO4 2 4 CuSO4 + SO2↑ + 2H2O Trends in the E0M2+/M Standard Electrode Potential In +2 state, Mn shows d5, Ni with d8 has completely filled t2g and Zn has completely filled d10). So, they show more negative E0 values than expected Hydration Energy 19 Radius/nm 18 Due to high charge density 17 16 15 14 13 12 Sc Ti V Cr Mn Fe Co Ni Cu Zn Y Zr Nb Mo Tc Ru Rh Pd Ag Cd La Hf Ta W Re Os Ir Pt Au Hg Ni2+ ion has the highest negative enthalpy of hydration among the elements of 3d series. Chemical Reactivity Transition metals vary widely in their chemical reactivity. Many are electropositive and dissolve in mineral acids. A few metals are noble or remain unreactive towards single acids. Standard electrode potential (V) Chemical Reactivity 0.5 Less negative E0 values 0 -0.5 -1 Across the series -1.5 -2 Ti V Cr Mn Fe Co Ni Observed values The E0M2+/M values indicate decreasing tendency to form divalent cation Cu Zn Calculated values Due to increase in the sum of first two ionisation enthalpies Magnetic Properties Each electron has an associated magnetic moment, due to Transition elements are paramagnetic in nature. Spin angular momentum Electron Direction of spin Orbital angular momentum Electron Nucleus Magnetic moment Spin-only magnetic moment (in BM) μ = √ n(n + 2) n = No. of unpaired electron(s) Where, Magnetic Moments of Mn2+ Ion Mn2+ [Ar] 3d54s0 5 unpaired electrons μ = √ 5(5 + 2) = 5.92 BM Calculated and Observed Magnetic Moments(BM) Magnetic moment increases with number of unpaired electrons. Magnetic moment Ion Configuration Unpaired electron(s) Calculated Observed Sc3+ 3d0 0 0 0 Ti3+ 3d1 1 1.73 1.75 Tl2+ 3d2 2 2.84 2.76 V2+ 3d3 3 3.87 3.86 Cr2+ 3d4 4 4.90 4.80 Mn2+ 3d5 5 5.92 5.96 Fe2+ 3d6 4 4.90 5.3-5.5 Co2+ 3d7 3 3.87 4.4-5.2 Ni2+ 3d8 2 2.84 2.9-3.4 Cu2+ 3d9 1 1.73 1.8-2.2 Zn2+ 3d10 0 0 Formation of Coloured Ions:3d Metal Ions Ti3+ Ti3+ : Purple Cr3+ : Green Mn2+ : Light pink Fe3+ : yellow Co2+ : pink Ni2+ : green Cu2+ : blue Mn2+ Cr3+ Co2+ Ni2+ Fe3+ Cu2+ Formation of Coloured Ions When an electron from a lower energy d orbital is excited to a higher energy d-orbital Due to this excitation, the compounds shows a color. Complex Compounds Compounds in which the metal atoms/ions bind to a number of anions/neutral molecules, by sharing of electrons and forming complex species with characteristic properties. Example: [Fe(CN)6]3–, [PtCl4]2–, etc. Haemoglobin Brown Ring Test In nitrate solution, add FeSO4, slowly add H2SO4 solution such that acid forms a layer below aqueous solution. A brown ring will be formed at the junction of the two layers. Formation of Complex Compounds Comparatively smaller sizes Reasons for complex formation High ionic charges Availability of d-orbitals for bond formation Catalytic Property of Transition Metals Transition metals show catalytic property due to the ability to Adopt multiple oxidation states Form complexes Catalytic Property of Transition Metals Iron(III) catalyses the reaction between iodide and persulphate ions. – 2– 2I + S2O8 2– I2 + 2SO4 Catalytic action, 2Fe3+ + 2I– 2– 2Fe2+ + S2O8 2Fe2+ + I2 2– 2SO4 + 2Fe3+ Formation of Interstitial Compounds Formation of Interstitial Compounds TiC Interstitial compounds are formed when small atoms like H, C, or N are trapped inside the crystal lattices of metals. Mn4N Fe3H VH0.56 TiH1.7 Usually, non-stoichiometric compounds are neither typically ionic nor covalent. Characteristics of Interstitial Compounds Higher than those of pure metals Some borides approach diamond in hardness. i High melting points. ii Very hard. iii Retain metallic conductivity. iv Chemically inert. Alloy An alloy is a blend of metals prepared by mixing the components. Alloys may be homogeneous solid solutions in which the atoms of one metal are distributed randomly among the atoms of the other. Alloy Formation Alloy Formation Properties of alloys: a Are hard Transition metals form alloys due to similar radii along with the other characteristics b Often have high melting points c Within about 15% of each other Show better conductivity Alloy Formation Ferrous alloys Steel Stainless Steel Cr, V, W, Mo, and Mn are used to produce various varieties. Alloy Formation Stainless steel Steel Main metal Other element Main metal Other metals Iron Carbon Iron Chromium, Nickel Alloy Formation Bronze Brass Main metal Other metal Main metal Other metal Copper Zinc Copper Tin Oxides Compounds of transition elements Oxoanions K2Cr2O7 KMnO4 Metal Oxides Oxidation Number Metal oxides are formed by reaction of metals with oxygen at high temperature. Group 3 4 5 6 +7 7 8 9 10 11 12 Mn2O7 +6 CrO3 +5 V2O5 +4 TiO2 V2O4 CrO2 MnO2 +3 Sc2O3 Ti2O3 V2O3 Cr2O3 Mn2O3 Fe2O3 Mn3O4 Fe3O4 Co3O4 +2 +1 TiO VO (CrO) MnO FeO CoO NiO CuO ZnO Cu2O Properties of Transition Metal Oxides Ionic character Properties of metal oxides Melting point Acidic or basic nature Ionic Character of Transition Metal Oxides Oxidation number of a metal in metal oxide increases Ionic character of the oxide decreases. Mn2O7 Covalent green oil Transition Metal Oxides: Melting Points Oxidation number ∝ 1 Ionic character Ionic character ∝ Melting point Hence, CrO3 and V2O5 have low melting points Oxidation number of a metal in metal oxide increases Acidic character of the oxide increases. Important Oxides of Transition Metals Strong acid Mn2O7 + H2O 3CrO3 + 2H2O 2HMnO4 H2CrO4+ H2Cr2O7 Strong acid Important Oxides of Transition Metals Oxides of Vanadium Oxides of Chromium +3 +4 +5 V2O3 V2O4 V2O5 More basic Less basic Amphoteric +2 +3 +6 CrO Cr2O3 CrO3 Basic Amphoteric Acidic Potassium Dichromate Preparation Properties K2Cr2O7 Structure Uses Preparation of K2Cr2O7 i Fusion of chromite ore with Na2CO3 4FeCr2O4 + 2Na2CO3 +7O2 ii Filtered 8Na2CrO4 + 2Fe2O3 + 8CO2 Yellow solution Reaction with H2SO4 2Na2CrO4 + 2H+ Na2Cr2O7 + 2Na+ + H2O Orange solution Preparation of K2Cr2O7 ii Reaction with KCl More soluble than K2Cr2O7 Na2Cr2O7 + 2KCl Crystallised K2Cr2O7 + 2NaCl Orange solution Preparation of K2Cr2O7 + 2– CrO4 +H +OH− Chromate Cr2O7 2– Dichromate Weak acid Alkaline solution Properties of K2Cr2O7 Oxidising nature Strong oxidising agent Na2Cr2O7 K2Cr2O7 In organic chemistry As a primary standard in volumetric analysis Also greater solubility in the polar solvent like CH3COOH K2Cr2O7 Properties of K2Cr2O7 In acidic medium Oxidising action +6 2– Cr2O7 + 14H+ + 6e– 2Cr3+ + 7H2O Standard electrode potential E0 = 1.33 V Breathe analyser Cr6+ ion (Orange) When orange K2Cr2O7 reacts with alcohol, it converts into green solution containing chromium sulfate. Cr3+ ion (Green) Properties of K2Cr2O7 Oxidation by acidified K2Cr2O7 Half reactions Iodides to Iodine 6I– → 3I2 + 6e– Sulphides to Sulphur 3H2S → 6H+ + 3S + 6e– Tin (II) to Tin (IV) 3Sn2+ → 3Sn4+ + 6e– Fe (II) to Fe (III) 6Fe2+ → 6Fe3+ + 6e– When orange K2Cr2O7 reacts with alcohol, it converts into green solution containing chromium sulfate. Oxide of Chromium Chromium (VI) peroxide (CrO5) Preparation 2– Cr2O7 + 2H+ + 4H2O2 Bright blue compound 2CrO5 + 5H2O Chromium (VI) Peroxide (CrO5) Structure _1 Peroxy bond _1 +6 _1 Peroxy bond _1 _2 Butterfly structure Chromate: Structure Chromate ion Dichromate ion d3s hybridised Tetrahedral Tetrahedral Tetrahedral Used in leather industry To prepare azo compounds Preparation Physical properties KMnO4 Structure Chemical properties Uses Potassium Permanganate: Preparation i Fusion of pyrolusite (MnO2) 2MnO2 + 4KOH + O2 Black solid 2K2MnO4 + 2H2O Dark green Disproportionation reaction in presence of an oxidising agent(KNO3 or KClO3) ii Disproportionation of 2− manganate (MnO4 ) 2− 3MnO4 + 4H+ − 2MnO4 + MnO2 + 2H2O Dark purple Potassium Permanganate: Preparation Commercial method Step-1 MnO2 Fused with KOH, oxidised with air or KNO3 MnO4 2− Step-2 2− MnO4 Laboratory method Electrolytic oxidation in alkaline solution MnO4− Oxidation of manganese(II) ion 2− 2Mn2+ + 5S2O8 + 8H2O 2− 2MnO4− + 10SO4 + 16H+ Colour of Intense color (dark purple) 2_ MnO4 and Manganate ion Green _ MnO4 Ions Permanganate ion Purple Magnetic Property of KMnO4 Heating effect Diamagnetic (no unpaired electron) Paramagnetic (one unpaired electron) 2KMnO4 Dark purple ∆ 513 K K2MnO4 + MnO2 + O2 Green Black Potassium Permanganate: Structure Tetrahedral Manganate ion Permanganate ion Potassium Permanganate: Chemical Properties Oxidising properties of KMnO4 in Oxidising nature Acidic medium In acidic medium +7 – MnO4 + 8H+ + 5e– Neutral or faintly alkaline medium Mn2+ + 4H2O Alkaline medium 0 E = 1.52 V Oxidising nature of KMnO4 in acidic medium 6HCl + 2KMnO4 + 5NaHSO3 -> 3H2O + 2KCl + 2MnCl2 + 5NaHSO4 Potassium Permanganate: Chemical Properties Oxidising nature of KMnO4 in acidic medium Liberation of I2 from I– solution: – 10I– + 2MnO4 + 16H+ 2Mn2+ + 8H2O + 5I2 Conversion of Fe(II) to Fe(III): – 5Fe2+ + MnO4 + 8H+ Green Mn2+ + 4H2O + 5Fe3+ Yellow Potassium Permanganate: Chemical Properties Oxidation of oxalate ion: 2– – 5C2O4 + 2MnO4 + 16H+ 2Mn2+ + 8H2O + 10CO2 Oxidation of Nitrite ion: – – + 5NO2 + 2MnO4 + 6H – 2Mn2+ + 5NO3 + 3H2O 2KMnO4(aq) + 16HCl(aq) 2KCl(aq) + 2MnCl2(aq) + 8H2O(l) + 5Cl2(g) Endpoint ❌ Permanganate titration is not carried out in the presence of hydrochloric acid because some of the hydrochloric acid gets oxidised to chlorine gas. Hence, we do not get the correct endpoint for the given titration. Potassium Permanganate: Chemical Properties In neutral medium +7 – MnO4 + + – 4H + 3e E0 = 1.69 V +4 MnO2 + 2H2O Potassium Permanganate: Chemical Properties Oxidising nature of KMnO4 in neutral medium Thiosulphate is oxidised to sulphate: – 2– 8MnO4 + 3S2O3 + H2O 8MnO2 + 6SO42– + 2OH – Oxidation of iodide to iodate: 2MnO4– + I– + H2O 2MnO2 + 2OH – + IO3– Potassium Permanganate: Chemical Properties The oxidation of manganous salt to MnO2 – 2MnO4 + 3Mn2+ + 2H2O ZnSO4 or ZnO catalyst 5MnO2 + 4H+ Potassium Permanganate: Chemical Properties In alkaline medium +7 – MnO4 + – e E0 = 0.56 V +6 MnO4 2– Uses of KMnO4 For bleaching of wool and textiles Decolourising of oils Decolourising of oils Silver Nitrate (AgNO3) Copper Oxide (CuO) Zinc Chloride (ZnCl2) Iron (II) oxide (FeO) White Vitriol (ZnSO4) Blue Vitriol (CuSO4.5H2O) Some Important d-Block Compounds Green Vitriol (FeSO4) Ferric Chloride (FeCl3) Silver Nitrate (AgNO3) It is called as lunar caustic because on contact with skin it produces a burning sensation like that with caustic soda along with the formation of finely divided silver (black coloured). Preparation When metallic Ag is dissolved in conc. HNO3 it produces AgNO3. Ag + 2HNO3 AgNO3 + NO2 + H2O Properties of AgNO3 Black metallic residue 1 2 Silver mirror test 2AgNO3 Δ 2Ag (Thermal Decomposition) 2AgNO3 + 2NaOH + 2NO2 + O2 H2O + 2NaNO3 + Ag2O Silver Oxide Ag2O + C6H12O6 Glucose 2Ag + C6H12O7 Gluconic acid Properties of AgNO3 3 AgNO3 + NaCl/NaBr/NaI NaNO3 + AgCl/AgBr/AgI White/pale yellow/Yellow ppt. 4 2AgNO3 + Na2S2O3 2NaNO3 + Ag2S2O3 White ppt. Ag2S2O3 + 3Na2S2O3 2Na3[Ag(S2O3)2] Soluble Properties of AgNO3 5 3AgNO3 + Na3PO4 3NaNO3 + Ag3PO4 Yellow ppt. 6 2AgNO3 + K2CrO4 2KNO3 + Ag2CrO4 Brick red ppt. 7 2AgNO3 + K2Cr2O7 2KNO3 + Ag2Cr2O7 Reddish brown ppt. Uses of AgNO3 1 4 For identifying presence of Cl‒, Br‒ and I‒ ions 2 In the preparation of inks and hair dyes. 5 Tollen's reagent 3 For making AgBr, used in photography. In preparation of silver mirror Zinc Chloride (ZnCl2) It is a deliquescent white solid when anhydrous. Preparation ZnCO3 ＋ 2HCl ZnO ＋ 2HCl ZnCl2 ＋ H2O ＋ CO2 ZnCl2 ＋ H2O Zinc Chloride (ZnCl2) Uses 01 For impregnating timber to prevent destruction by insects. As dehydrating agent when anhydrous. 03 ZnO.ZnCl2 is used in dental fillings. 02 Zinc Sulphate (ZnSO4) Colourless, crystalline solid, soluble in water which is used in dietary supplements. It was historically called as white vitriol. Preparation Zn ＋ dil. H2SO4 ZnSO4 ＋H2 ZnO ＋ dil. H2SO4 ZnSO4 ＋H2O Zinc Sulphate (ZnSO4) Uses 01 In eye lotions. Lithopone(ZnS + BaSO4) is used as white pigment. 03 02 Used in the prevention and treatment of zinc deficiency. Blue Vitriol (CaSO4) Preparation CuO ＋ dil. H2SO4 Cu(OH)2 ＋ dil. H2SO4 CuSO4 ＋ H2O CuSO4 ＋ 2H2O Properties It is crystallised as CuSO4.5H2O and it is called as blue vitriol. It is used as a herbicide and a fungicide, as battery electrolytes and as mordant during a vegetable dyeing process. Copper Oxide (CuO) Preparation CuCO3.Cu(OH)2 Δ 2CuO ＋H2O ＋CO2 Malachite Green Cu(OH)2 Properties 1 Δ CuO ＋ H2O It is insoluble in water. 4CuO Black > 1100°C 2 It decomposes when heated above 1100°C 2Cu2O ＋O2 Red FeO Preparation Properties FeC2O4 Δ In absence of air FeO ＋CO ＋ CO2 It is stable at high temperatures and on cooling slowly disproportionates into Fe3O4 and Fe. 4FeO Fe3O4 ＋Fe Green Vitriol (FeSO4) Preparation Properties 1 2 Fe(scarp)＋ H2SO4 FeSO4 ＋ H2 FeS ＋ dil. H2SO4 FeSO4 ＋ H2S It undergoes oxidation forming basic ferric sulphate It act as a reducing agent 3 It is crystallised as green vitriol(FeSO4.7H2O) Ferric Chloride (FeCl3) Preparation 2Fe ＋ 3Cl2 (dry) Dark red deliquescent solid Δ Iron wire 2FeCl3 Anhydrous 2Fe(OH)3 + 3HCl FeCl3 + 3H2O The solution on evaporation and cooling deposits yellow crystals of hydrated ferric chloride, FeCl3.6H2O. Ferric Chloride (FeCl3) Properties It dissolves in water. The solution is acidic in nature due to its hydrolysis. The solution is stabilised by the addition of HCl to prevent hydrolysis. FeCl3 + 3H2O FeCl3 + 3NH4OH Fe(OH)3 + 3HCl Fe(OH)3 + 3NH4Cl Reddish brown ppt. Ferric Chloride (FeCl3) Properties FeCl3 + 3NH4CNS Fe(SCN)3 + 3NH4Cl Deep red color complex 4FeCl3 + 3K4[Fe(CN)6] Potassium ferrocyanide Fe4[Fe(CN)6]3 + 12KCl Prussian blue (Ferri ferrocyanide) Periodic Table d-Block elements f-Block elements Point to Remember La and Ac closely resemble the lanthanoids and actinoids, respectively. Included in discussion of the respective series besides the 14 elements. Lanthanoids Electronic configurations Atomic and ionic size Lanthanoids (Ln) Oxidation states Physical properties Chemical properties Uses Lanthanoids: Electronic Configuration General configuration Variable occupancy 4f1-14 5d0-1 6s2 d1 d0 Ce, Gd, Lu All other elements Lanthanoids: Electronic Configuration Electronic configurations of lanthanum and lanthanoids Electronic configuration Atomic number Name 57 Lanthanum La 5d1 6s2 58 Cerium Ce 4f1 5d1 6s2 59 Praseodymium Pr 4f3 6s2 60 Neodymium Nd 4f4 6s2 61 Promethium Pm 4f5 6s2 62 Samarium Sm 4f6 6s2 63 Europium Eu 4f7 6s2 64 Gadolinium Gd 4f7 5d1 6s2 Symbol Ln Lanthanoids: Electronic Configuration Electronic configurations of lanthanum and lanthanoids Electronic configuration Atomic number Name 65 Terbium Tb 4f9 6s2 66 Dysprosium Dy 4f10 6s2 67 Holmium Ho 4f11 6s2 68 Erbium Er 4f12 6s2 69 Thulium Tm 4f13 6s2 70 Ytterbium Yb 4f14 6s2 71 Lutetium Lu 4f14 5d1 6s2 Symbol Ln Lanthanoids: Atomic and Ionic Size Lanthanoids (left to right) La → Lu Overall decrease in atomic and ionic radii Due to lanthanoid contraction Lanthanoids: Atomic Sizes Overall decrease in atomic size Half filled f-orbital Eu 200 Atomic radii/pm 195 190 La 185 180 Ce Pr Pm Nd Sm Gd Tb Dy 175 170 Ho Er Tm Yb 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Atomic number Lanthanoids: Ionic Sizes Overall decrease in ionic size Sm2+ 110 Eu2+ La3+ Ce3+ Pr3+ Nd3+ Pm3+ Sm3+ Eu3+ Tm2+ Gd3+ Ce4+ Yb2+ Tb3+ Dy3+ 4+ Pr Ho3+ Er3+ 3+ Tm Yb3+ Lu3+ Tb4+ Ionic radii/pm 100 90 57 59 61 63 65 Atomic number 67 69 71 Lanthanoid Contraction Decrease in sizes fairly regular for Ln as compared to transition elements Electron density is equally distributed Three regions where electron Two regions density falls to zero where electron One region density falls to where electron zero density falls to zero Lanthanoids: Oxidation States Common oxidation state Common oxidation state is Ln(lll) Occasionally +2 and +4 oxidation states are also obtained Easy removal of two 6s and one 5d (or 4f) electrons except Eu and Yb Extra stability of empty, half-filled and fully filled f subshell Lanthanoids: Oxidation States Ce4+ [Xe] 4f0 Tb4+ [Xe] 4f 7 Ce3+ Eo = + 1.74 V [Xe] 4f Tb3+ 1 Eu2+ [Xe] 4f7 All these ions shift back to +3 state hence they act as reducing or oxidising agents. [Xe] 4f8 [Xe] 4f Yb2+ 14 Eu3+ [Xe] 4f 6 Yb3+ [Xe] 4f13 Samarium(Sm) Metal Lanthanoids are silvery white soft metals and tarnish rapidly in air. Gadolinium(Gd) Metal Samarium (Steel Hard) The hardness increases with increasing atomic number, samarium being steel hard. High melting points Their melting points range between 1000 to 1200 K but samarium melts at 1623 K. Density Density and other properties change smoothly except for Eu and Yb and occasionally for Sm and Tm. High electrical conductivity High thermal conductivity They are good conductors of heat and electricity. Trivalent lanthanoid ions Many trivalent lanthanoid ions are coloured both in the solid state and in aqueous solutions due to incomplete filling of f-orbitals except La3+ and Lu3+ Pr+3 (aq. solution) Sm+3 (aq. solution) Colour of Lanthanoid Ions La3+ Lu3+ [Xe] 4f0 [Xe] 4f14 No unpaired electron Colourless Magnetic Properties f0 type f14 type La3+ & Ce4+ Yb2+ & Lu3+ Other than these, all other ions are paramagnetic. Point to Remember Ionisation enthalpies are fairly low and comparable to alkaline earth metals. Hence, they are good reducing agents. La3+, Gd3+ and Lu3+ have abnormally low third ionisation enthalpy values. Extra stability of f0, f7 and f14 orbitals Lanthanoids: Ionisation Enthalpy o La2+ [Xe] 4f0 5d1 2+ Gd [Xe] 4f7 5d1 Lu2+ [Xe] 4f14 5d1 E values La3+ [Xe] 4f0 3+ Gd [Xe] 4f7 Lu3+ [Xe] 4f14 Low values of ionization enthalpy (III) Good reducing agents due to low IE values Ln3+ (aq) + 3e– Eo ≈ Except Eu = -2.0 V Ln (s) -2.2 to -2.4 v Lanthanoids : Chemical Properties The earlier members of the series are quite reactive Like calcium However, with increasing atomic number, they behave more like aluminium. Typically form compounds which are ionic and trivalent(Ln3+) Chemical Reaction of Lanthanoids Ln2O3 H2 Basic LnN Heated with S Ln With C, 2773 K Ln2S3 With halogens LnX3 Basic Ln(OH)3 + H2 LnC2, Ln3C and Ln2C3 Uses of Inner Transition Metals Alloy steels Phosphors Catalysts in petroleum cracking Phosphors in television screen Mischmetall Mischmetal bullets and shells It consists of a lanthanoid metal (~ 95%), iron (~ 5%) and traces of S, C, Ca and Al. Mischmetal in lighter flint Radioactive and used in nuclear reactors Chernobyl disaster Hiroshima and Nagasaki bomb attack Radiotherapy Actinoids Uranium is the heaviest naturally occurring element. After uranium, 12 more elements has been artificial synthesized (atomic number more than 92) and are called the transuranium elements Actinoids are radioactive elements Earlier members Relatively, long half-lives Latter members Half-life: A day to 3 minutes Prepared only in nanogram quantities Lr (lawrencium) Electronic configurations Actinoids (An) Atomic and ionic size Oxidation states General characteristics Actinoids: Electronic Configuration Electronic configurations of actinium and actinoids Atomic number Name 89 Actinium 90 Symbol Electronic configuration An An3+ Ac 6d1 7s2 5f0 Thorium Th 6d2 7s2 5f1 91 Protactinium Pa 5f2 6d17s2 5f2 92 Uranium U 5f3 6d17s2 5f3 93 Neptunium Np 5f4 6d17s2 5f4 94 Plutonium Pu 5f6 7s2 5f5 95 Americium Am 5f7 7s2 5f6 Actinoids: Electronic Configuration Electronic configurations of actinium and actinoids Atomic number Name 96 Curium 97 Symbol Electronic configuration An An3+ Cm 5f7 6d1 7s2 5f7 Berkelium Bk 5f9 7s2 5f8 98 Californium Cf 5f10 7s2 5f9 99 Einstenium Es 5f11 7s2 5f10 100 Fermium Fm 5f127s2 5f11 101 Mendelevium Md 5f13 7s2 5f12 102 Nobelium No 5f14 7s2 5f13 103 Lawrencium Lr 5f146d1 7s2 5f14 Actinoids: Electronic Configuration Electronic configurations of actinium and actinoids Atomic number Name 89 Actinium 90 Symbol Electronic configuration An An3+ Ac 6d1 7s2 5f0 Thorium Th 6d2 7s2 5f1 91 Protactinium Pa 5f2 6d17s2 5f2 92 Uranium U 5f3 6d17s2 5f3 93 Neptunium Np 5f4 6d17s2 5f4 94 Plutonium Pu 5f6 7s2 5f5 95 Americium Am 5f7 7s2 5f6 Actinoids: Electronic Configuration Electronic configurations of actinium and actinoids Atomic number Name 96 Curium 97 Symbol Electronic configuration An An3+ Cm 5f7 6d1 7s2 5f7 Berkelium Bk 5f9 7s2 5f8 98 Californium Cf 5f10 7s2 5f9 99 Einstenium Es 5f11 7s2 5f10 100 Fermium Fm 5f127s2 5f11 101 Mendelevium Md 5f13 7s2 5f12 102 Nobelium No 5f14 7s2 5f13 103 Lawrencium Lr 5f146d1 7s2 5f14 Half filled f7 Fully filled f14 The difference between the energy levels of 5f and 6d orbitals are small Thus in Ac, Th, Pa, U and Np electrons may occupy either 5d or 6f orbitals. 5f orbital extend in space, comparatively more than 4f orbital, hence 5f electrons participate in bonding to a greater extent Actinoids: Atomic and Ionic sizes Due to actinoid contraction Gradual decrease in the size of atoms or An3+ ions across the series Oxidation States of Actinium and Actinoids Oxidation states form regular pyramid The actinoids resemble the lanthanoids in having more compounds in +3 state than in the +4 state. Ac Th Pa U +3 Np Pu Am Cm Bk Cf Es Fm Md No Lr +3 +3 +3 +3 +3 +3 +3 +3 +3 +3 +3 +3 +3 +4 +4 +4 +4 +4 +4 +4 +4 +5 +5 +5 +5 +5 +6 +6 +6 +6 +7 +7 Actinoids : General Characteristics Physical properties Actinoid metals are all silvery in appearance but display a variety of structures. Due to irregularities in metallic radii which are far greater than in lanthanoids Actinoids : Chemical Properties Hydrochloric acid attacks all metals but most metals are less affected by nitric acid. Actinoids are highly reactive metals H2O (Boil) ✔ 2 Most non-metals ✔ 3 HCl ✔ 4 HNO3 1 Due to formation of protective oxide layer. Uses of d & f Block Elements Alloying metals like Cr, Mn, Ni are used in production of Iron and steels which are most important construction materials. TiO2 as white pigment Dry cell battery Application as Catalysts Important Catalyst Process V2O5 Contact process Ziegler catalyst [TiCl4 with Al(CH3)3] Polythene manufacturing Iron Haber process Nickel Hydrogenation of fats PdCl2 Wacker process Nickel complex Polymerisation of alkynes and benzene