d and f block elements/Transition and inner transition elements

Contains all topics from d and f block along with steps for extraction Fe using blast furnace. The source is 12th MAHARASHTRA state board textbook.

1. TRANSITION AND INNER TRANSITION ELEMENTS PRESENTED BY: FREYA CARDOZO By Freya Cardozo

2. Transition elements The general electronic configuration of transition elements is (n-1) d1-10 ns 1-2 . The transition elements are placed in the periods 4 to 7 and groups 3 to 12 those constitute 3d,4d,5d and 6d series By Freya Cardozo

3. What are Transition elements Elements that have a partially filled d orbital in their ground state or one of its oxidation state. G.R why Zn is not a transition element but Cu is. Since zinc has completely filled (n - 1)d orbital in the ground state ( 3d 10 4s 2 ) and (3d 10 ) in its common oxidation state +2, it is not regarded as transition element. Copper in the elementary state (3d 10 4s 1 ) contains filled 3d orbitals but in the +2 oxidation state it has partly filled 3d orbital (3d 9 ), hence copper is a transition element. By Freya Cardozo

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5. Oxidation State By Freya Cardozo

6. Give reason Why Cu and Cr show anomalous E.C Mainly due to the fact that half filled and fully filled orbitals have extra stability The general electronic configuration of the elements of the 3d series is 3d 1-10 4s 2 with the exceptions of Cr and Cu. The 3d and 4s orbitals are close in energy and in order to gain extra stability the last electron instead of occupying 4s orbital occupies the 3d orbital that assigns Cr the 3d 5 4s 1 and Cu 3d 10 4s 1 configuration By Freya Cardozo

7. Physical properties They are hard, lustrous, malleable and ductile They are good conductors of heat and electricity They possess high MP BP Except Zn, Cd , Hg and Mn , all the other transition elements have one or more typical metallic structures at ambient temperature. These transition metals (with the exception of Zn, Cd and Hg) are very hard and have low volatility By Freya Cardozo

8. Ionic radius For the same oxidation state, with an increase of nuclear charge a gradual decrease in ionic radii was observed. The trend is pronounced for the divalent ions of the first transition series (Cr 2⊕ - 82 pm, Cu 2⊕ - 72 pm). The oxidation states of the same element shows difference of one unit such as M ⊕ , M 2⊕ , M 3⊕ ,M 4⊕ and so on. With higher oxidation state the effective nuclear charge also increases and hence, decrease of ionic radii can be observed from M 2⊕ to M 3⊕ By Freya Cardozo

9. Atomic radii decreases gradually across the period As we move across a transition series from left to right the nuclear charge increases by one unit at a time. The last filled electron enters a penultimate (n-1)d subshell . However, d orbitals in an atom are less penetrating or more diffused and, therefore d electrons offer smaller screening effect. The result is that effective nuclear charge also increases as the atomic number increases along a transition series. Hence the atomic radii decrease gradually across a transition series from left to right. By Freya Cardozo Size decreases across a period

10. Ionization enthalpy The I.E for d block elements lies between the s and p blocks Across the group as the size decrease Ionization enthalpy increases IE3>IE2> IE1 Depending on condition the type of bond is decided Lower O.S – Ionic bond High o.s – Covalent bond By Freya Cardozo Ionization energy or Ionisation energy, denoted Eᵢ, is the minimum amount of energy required to remove the most loosely bound electron, the valence electron, of an isolated neutral gaseous atom or molecule Size decreases across a period I.E  ↑ Across the period

11. Ionisation enthalpy G.R ionization enthalpy for 3 rd transition series is more than 1 st and 2 nd series The atoms of elements of third transition series possess filled 4f- orbitals . 4f orbitals show poor shielding effect on account of their peculiar diffused shape. As a result, the valence electrons experience greater nuclear attraction. A greater amount of energy is required to ionize elements of the third transition series By Freya Cardozo

12. Metallic character Metallic character is due to the : VACANT d orbitals Low ionisation enthalpy Hardness of metals is due to the covalent bond which is possible because of the unpaired (n-1)d electrons in these elements Mostly they show HCP, ccp, bcc lattice structure Hardness, high melting points and metallic properties of the transition elements indicate that the metal atoms are held strongly by metallic bonds with covalent character. By Freya Cardozo

13. Magnetic properties They show magnetic properties due to the unpaired electrons 3 types Dimagnetic – Replled by magnetic field Paramagnetic- attracted to mag field Ferromagnetic- strongly attracted. EG. Fe, Co, Ni Magnetic moment is sum of spin angular momentum and orbital angular momentum µ= n(n + 2) BM n = no.of unpaired ELECTRONS By Freya Cardozo Paired e- : Diamagnetic Unpaired e-: Paramagnetic

14. QUESTIONS Which one of the following is dimagnetic a. Cr2⊕ b. Fe3⊕ c. Cu2⊕ d. Sc3⊕ Magnetic moment of a metal complex is 5.9 B.M. Number of unpaired electrons in the complex is a. 2 b. 3 c. 4 d. 5 By Freya Cardozo

15. QUESTIONS What is the magnetic moment for Cr3+ a. equal to 1.73 BM, b. less than 1.73 BM or c. more than 1.73 BM ? Why salts of Sc3⊕, Ti4⊕, V5⊕ are colourless ? Calculate the spin only magnetic moment of divalent cation of a transition metal with atomic number 25. By Freya Cardozo

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17. d block elements are remarkably coloured By Freya Cardozo

18. A substance appears coloured if it absorbs a portion of visible light. The colour depends upon the wavelength of absorption in the visible region of electromagnetic radiation By Freya Cardozo

19. Reasons for color in transition metals 1. presence of unpaired d electrons 2. d - d transitions 3. nature of ligands attached to the metal ion 4. geometry of the complex formed by the metal ion By Freya Cardozo

20. Unpaired ELECTRONS And d-d transition REASON FOR COLOUR- d-d transition By Freya Cardozo

21. Geometry of complex ion When cobalt chloride (Co2⊕) is dissolved in water, it forms a pink solution of the complex [Co(H2O)6]2⊕ which has octahedral geometry. But when this solution is treated with concentrated hydrochloric acid, it turns deep blue. This change is due to the formation of another complex [CoCl4]2 which has a tetrahedral structure. By Freya Cardozo

22. Charge transfer MnO4- ion has an intense purple colour in solution. In MnO4 - , an electron is momentarily transferred from oxygen (O) to metal, thus momentarily changing O2 to Oand reducing the oxidation state of manganese from +7 to +6. For charge transfer transition to take place, the energy levels of the two different atoms involved should be fairly close. Colours of Cr 2 O 7 2- , CrO 4 , Cu 2 O and Ni-DMG (where DMG = dimethyl glyoxime ) complex are other examples By Freya Cardozo

23. Catalytic properties because of their ability to participate in different oxidation-reduction steps of catalytic reactions. This possible due to unpaired e-s in incomplete d orbitals variable o.s Large surface area In homogeneous catalysis reactions, the metal ions participate by forming unstable intermediates. In heterogeneous catalysis reactions on the other hand, the metal provides a surface for the reactants to react. By Freya Cardozo

24. Examples of important catalyst Mo/Fe – Habers process Co- Th Fischer Tropsch process --- gasoline synthesis Ni – cataylic hydrogenation Platinised asbestos- solid catalyst --- contact process for manu of sulfuric acid from SO 2 and O 2 Fe-Cr – production of CO 2 frm CO By Freya Cardozo

25. Interstitial compOunds When small atoms like hydrogen, carbon or nitrogen are trapped in the interstitial spaces within the crystal lattice, the compounds formed are called interstitial compounds Steel and cast iron are examples of interstitial compounds of carbon and iron Properties Good conduction MP BP higher than parent Density less than parent carbides of metals are inert and hard hydrides of transition metals are Powerful reducing agents By Freya Cardozo

26. Alloys Alloys are mixtures of metals classification 1. Ferrouss alloys have atoms of other elements distributed randomly in atoms of iron in the mixture. As percentage of iron is more, they are termed ferrous alloys eg. nickel steel, chromium steel, stainless steel etc. All steels have 2% carbon 2. Non-ferrous alloys are formed by mixing atoms of transition metal other than iron with a non transition element. eg. brass, which is an alloy of copper and zinc. Ferrous and non-ferrous alloys are of industrial importance. By Freya Cardozo

27. Uses Bronze=Cu+Tin Tough, strong and corrosion resistant Cupra nickel – machine parts of ships stainless steel – air crafts Nichrome=Ni+Cr – turbine engines Titanium alloys --- can withstand high temp Components of Nichrome alloy are are a. Ni, Cr, Fe b. Ni, Cr, Fe, C c. Ni, Cr d. Cu, Fe By Freya Cardozo

28. Preperation of potassium dichromate K2Cr2O7 Chromite ore =FeO.Cr 2 O 3 to Sodium chromate Na 2 CrO 4 --- anhydrous sodium carbonate And flux of like in air Sodium chromate to Sodium dichromate Na 2 Cr 2 O 7 ---- Sulphuric acid and water Sodium dichromate to potassium dichromate K 2 Cr 2 O 7 --- Potassium chloride By Freya Cardozo FeO.Cr 2 O 3 Na 2 CrO 4 Na 2 Cr 2 O 7 K 2 Cr 2 O 7 OUTLINE

29. Step 1 STEP 1 By Freya Cardozo

30. Step 2 STEP 2 By Freya Cardozo

31. Step 3 STEP 3 By Freya Cardozo

32. Chemical properties of potassium dichromate Reactant Colour (Before) K 2 SO 4 Cr 2 (SO 4 ) 3 H2O Special byproduct Color K 2 Cr 2 O 7 +H 2 SO 4 KI Potassium iodide Orange ✓ ✓ ✓ I 2 Brown K 2 Cr 2 O 7 +H 2 SO 4 H 2 S Hydrogen sulphide Orange ✓ ✓ ✓ S Green solution+ Yellow ppt By Freya Cardozo

33. Reaction with KI The oxidation of KI with acidified potassium dichromate produces I 2 This changes the solution to brown Potassium dichromate is reduced to chromic sulphate By Freya Cardozo

34. Reaction with H 2 S The reaction leads to the pptn of S which appears as pale yellow ppt Potassium dichromate is reduced to chromic sulphate Due to the production of chromic sulphate the orange solution turns green By Freya Cardozo

35. KM n O 4 – Potassium permanganate Preparation method Chemical oxidation Electrolytic oxidation By Freya Cardozo

36. Chemical method MnO 2 manganese dioxide  K 2 MnO 4 Potassium mangante (green) – Caustic potash KOH Potassium chlorate KClO 3 – oxidising agent Dispropotionation in neutral or acidic medium  KMnO 4 + MnO 2 Filteration to glass wool By Freya Cardozo

37. Electrolytic oxidation Alkaline solution of manganate ion is electrolysed between iron electrodes seperated by a diaphram At anode the oxygen evolved is used to reduce manganate to permanganate Overall reaction The solution is evaporated and filtered to obtain the crystals By Freya Cardozo

38. Chemical properties of KMnO 4 In acidic medium- Oxidising action Iodide to Iodine Fe 2+ to Fe 3+ H 2 S to S Oxidation of oxalic acid H 2 C 2 O 4 In neutral medium or weakly alkaline medium Iodide to Iodate Oxidation of thiosulphate to sulphate Manganous salt to manganese dioxide By Freya Cardozo

39. In acidic medium By Freya Cardozo

40. Acidic medium By Freya Cardozo

41. Neutral or alkaline medium By Freya Cardozo

42. USES Antiseptic Test for unsaturation Quantitative analysis- Halide detection Volumetric analysis- For reducing agents Oxidising agent- labs and industry Why is KMnO 4 such a good oxidising agent? By Freya Cardozo

43. QUESTIONS By Freya Cardozo

44. Inner transition elements Orbital lies much inside the d orbital,in relation to the transition metals the f block elements are called inner transition elements. f – 1 to 14 electrons, d – 0 or 1 and s – 2 electrons 2 series : Lanthanoids and Actinoids Lanthanoids – characterizied by filling of 4f Actinoids - characterizied by filling of 5f 14 elements in each By Freya Cardozo

45. f block elements Those elements in which the outermost electrons enter the f subshell They belong to the 6 th and 7 th period Placed seperately at the bottom of the table By Freya Cardozo

46. Properties of f block elements These metals are soft with moderate densities of about 7 g cm-3. They have high melting point They are quite reactive similar to the alkali metals than d block metals common oxidation state for lanthanoids is +3 +2 is also very common among these, higher O.S like +4 is unusual ( exptn - Ce ) By Freya Cardozo

47. Lanthanoids - Rare earth elements They were know as rare because it was difficult to extract them economically from their ores By Freya Cardozo

48. G.R: Lanthanoids have lower heat of atomization than transition metals. The energy required to break up the metal lattice is heat of atomization. This is because with d electrons, transition metals are much harder and require high heat of atomization. Europium and ytterbium have the lowest enthalpies of vaporization and largest atomic radii of lanthanoids , resemble barium. By Freya Cardozo

49. Radii Their ionic radii decrease from 117 pm of La to 100 pm for Lu. This is because 5f orbitals do not shield the outer 5s and 5p electrons effectively, leading to increase in effective nuclear charge and decrease in the ionic size. By Freya Cardozo

50. Reactions with Ln Reactants Reactants Product Ln C LnC Ln H2O Ln (OH)3 Ln O2 Ln2O3 Ln N2 LnN Ln X LnX3 Ln = Lanthanoids By Freya Cardozo

51. Basicity of lanthanoids All the lanthanoids form hydroxides ofthe general formula Ln (OH)3 These are ionic and basic. Since the ionic size decreasesfrom La3+ to Lu3+, the basicity of hydroxides decreases. La(OH)3 is the strongest base while Lu(OH)3 is the weakest base. By Freya Cardozo

52. Electronic configuration Generally the E.C for lanthanoids is represented as [ Xe ] 4f 0-14 5d 0-1 6s 2 Xe = Xenon, Z= 54 The E.C for Xe is 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 By Freya Cardozo

53. Exceptions The electrons first fill up the 6s 4f and 5d are very close in energy In case of lanthanum the 5d oribtal has lower energy In case of Gd and Yb the anamolous behaviour is observed As half filled and fully filled electrons have extra stability Thus general E.C for lanthanoids is [ Xe ] 4f 0-14 5d 0-1 6s 2 By Freya Cardozo

54. Ionisation enthalpy What is ionisation enthalpy? As size increases, ionisation enthalpy decreases since the last electron experiences lesser pull from the nucleus Across the period, size decreases thus I.E increases Why some elements have variable O.S states but others only a few? Can ionisation enthalpy justify these? By Freya Cardozo

55. QUESTION HINT: Energy required to remove unpaired electrons is lesser than that to remove paired electrons Check the energy of subshell , lower the energy easy to remove the last electron n+l lower: lesser energy the subshell has By Freya Cardozo

56. Oxidation state G.E.C = [ Xe ] 4f 0-14 5d 0-1 6s 2 thus the common O.S is +3 i.e 2 e- from 6s and the order from d/f subshell The 4f electrons are shielded by the inner 5s and 5p orbitals , they are tightly bond to the nucleus. Thus they do not take part in the bonding Some show O.S +2 and +4 this is due to f , f 7 , f 14 E.C By Freya Cardozo

57. Colour These elements are coloured due to the f-f transition which corresponds to the energy in the visible spectrum The colour of ions with nf electrons= (14-n)f electrons COLOUR IN LANTHANOIDS By Freya Cardozo

58. What is shielding effect The decrease in the net force of attraction between the electrons present in the outer shell of an atom in the direction of nucleus due to change in linearity of the electric lines of forces between them due to the presence of high election density in the inner shells in the same atom is known as screening effect. By Freya Cardozo

59. Atomic radiI Across the period the radii decreases as the size decreases The decrease in lanthanoids is very steady this is called the LANTHANOID CONTRACTION As we move left to right the nuclear charge increases by +1 and an electron is added The electron is added to the same 4f subshell Due to their diffused shape the 4f electrons shield each other poorly from the nuclear charge With increasing atomic no. the effective nuclear charge increases thus pulling the 4f shell closer, causing it to cntract By Freya Cardozo

60. Magnetic moment µ=square root of n(n + 2) BM n = no.of unpaired ELECTRONS Calculate magnetic moment for La 3+ La -57 [ Xe ]4f 5d 1 6s 2 n=1 Magnetic moment By Freya Cardozo

61. Applications In hybrid cars, superconductors and permanent magnets Used in the colour tubes of computers and T.Vs since they produce visible light over a small wavelength upon bombarding with e-s ( Eu,Y )2O3 – red colour There types of Ln are used to get 3 primary colours Luminescent materials Nd : YAG laser Applications of Lanthanoids By Freya Cardozo

62. Actinoids By Freya Cardozo

63. Actinoids Starts with Thorium Z=90 and ends with Lawrencium Z=103 They are all radioactive and man-made High M.P, B.P, density The electronic configuration of actinoids is [ Rn ] 5f 0-14 6d 0-2 7s 2 , where Rn is the electronic configuration of radon. most stable oxidation state in actinoids is +3. The highest however actinoids show a variety of O.S from +2 to +8 By Freya Cardozo

64. DIFFERENCES BETWEEN LANTHANOIDS AND ACTINOIDS By Freya Cardozo

65. Oxidation state Early lanthanoids show variable O.S this is similar to transition elements than lanthanoids This pattern is seen mostly due to the ability of 5f orbital to participate in bonding A ready loss of 5f electrons by early actinoids indicates that these electrons are much closer in energy to 7s and 6d electrons than the 4f electrons to 6s and 5d electrons as in lanthanoids G.E.C [ Rn ] 5f0-14 6d0-2 7s2 Eg . uranium has electronic configuration of [ Rn ]7s2 5f 36d1. The formation of +6 oxidation state corresponds to an electronic configuration of [ Rn ]. By Freya Cardozo

66. Half filled and fully filled orbitals have extra stability. Thus one electron from f is promoted to d By Freya Cardozo

67. The overall gradations among the different blocks of the periodic table Transition elements- d block Lanthanoids -f block Pre- transition – s block By Freya Cardozo

68. Actinoid contraction 5f 6d 7s are almost same energy in actinoids The 7s electrons shield the 5f and 6d orbitals from nuclear charge , thus they expand a little. Therefore, they have size greater than lanthanoids But the decreases in radii is not as prominent, due to the shielding effect of f orbitals By Freya Cardozo

69. Application OF ACTNOIDS Half lives of Thorium & Uranium are so long that the amount of radiation emitted is negiligble , thus they can be used in everyday life. Th (IV) oxide, ThO2 with 1% CeO2 was used as a major source of indoor lighting before incandescent lamps came into existence only because these oxides convert heat energy from burning natural gas to an intense light. Even today, there is a great By Freya Cardozo

70. Postactinoid elements POST ACTINOID ELEMENTS Elements with atomic number greater than 92 are called ‘ Transuranium ’. Elements from atomic number 93 to 103 now are included in actinoid series and those from 104 to 118 are called as postactinoid elements. They are included as postactinoids because similar to actinoid elements, they can be synthesized in the nuclear reactions. So far, nine postactinoid elements have been synthesized. Half life is in secs 2.8 x 10^-4, thus difficult to study reactions Rutherfordium forms a chloride, RfCl4, similar to zirconium and hafnium in the +4 oxidation state. Dubnium resembles to both, group 5 transition metal, niobium(V) and actinoid , protactinium(V). By Freya Cardozo

71. Questions ix. In which of the following series all the elements are radioactive in nature a. Lanthanides b. Actinides c. d-block elements d. s-block elements x. Which of the following sets of ions contain only paramagnetic ions a. Sm3⊕, Ho3⊕, Lu3⊕ b. La3⊕, Ce3⊕, Sm3⊕ c. La3⊕, Eu3⊕, Gd3⊕ d. Ce3⊕, Eu3⊕, Yb3⊕ xi. Which actinoid , other than uranium, occur in significant amount naturally? a. Thorium b. Actinium c. Protactinium d. Plutonium By Freya Cardozo

72. Metal extraction By Freya Cardozo

73. Definition Mineral : naturally occuring substance found in the earth’s crust containing inorganic salts, solids, siliceous matter etc, is called a mineral. Ore: The mineral which contains high percentage of the metal and from which the metal can be extracted economically is called an ore DEFINITONS By Freya Cardozo

74. Metallurgy Commercial extraction of metals from their ores is called metallurgy. By Freya Cardozo

75. Types of metallurgy Pyrometallurgy : A process in which the ore is reduced to metal at high temperature using reducing agents like carbon, hydrogen, aluminium , etc. is called pyrometallurgy . Hydrometallurgy : The process of extracting metals from the aqueous solution of their salts using suitable reducing agent is called hydrometallurgy. Electrometallurgy : A process in which metal is extracted by electrolytic reduction of molten (fused) metallic compound is called electrometallurgy TYPES OF METALLURGY By Freya Cardozo

76. General methodology Extraction of ore Concentration of ore – removing impurities of other metals, sand, dust particles impurities termed as gangue are removed from the ore and the ore gets concentrated. The sand, mud and other unwanted impurities which remain mixed with the ore deposit are called gangue. Methods – Hydraulic classifiers Froth floation Magnetic seperation Convert to its oxides – Can be done by either Roasting . Calcination Obtaining pure metal By Freya Cardozo

77. Steps By Freya Cardozo

78. Extraction of iron Ore – Haematite ore (Fe 2 O 3 ) Gangue -SiO 2 + Al 2 O 3 + phosphates Concentration – Hydraulic classifier The powdered ore is washed in a powerful current of water introduced into the hydraulic classifier. The lighter gangue particles are separated and the concentrated ore is collected at the bottom. Converting into the oxide Roasting : The concentrated ore is heated In a current of air. The sulfur and arsenic impurties present in the ore get converted into their oxides and escape as vapour . Ferrous oxide in the ore is converted to Fe 2 O 3 4FeO + O 2 --  2 Fe 2 O 3 STEPS IN EXTRACTION OF Fe ore By Freya Cardozo

79. Hydraulic classifier CONCENTRATION OF ORE ! By Freya Cardozo

80. By Freya Cardozo

81. BLAST FURNANCE- Smelting Tall cylindrical steel tower lined with refractory bricks. The height=25 m and diameter =5 to10 m. Working- counter current principle : Charge comes down and hot gases move up the tower. The furnace is comprised of 3 parts – Hearth, 2. Bosh and 3. Stack Ore is introduced in the furnace through a cup and cone arrangement Ensures uniform distribution and prevents loss of gases A blast of preheated air is introduced into the furnance below the bosh through tuyeres . By Freya Cardozo

82. By Freya Cardozo

83. 1.Zone of combustion The formation of CO is exothermic and thus temperature is 2000K Some CO decomposes to C The hot CO gas moves upward and thus heats up the incoming charge Therefore CO acts as a fuel and reducing agent By Freya Cardozo

84. Zone of reduction By Freya Cardozo

85. Zone of slag formation The gangue present in the ore is converted to slag. This slag can be used for making road foundation. Temperature of this zone is 1200 K. The gangue contains silica, alumina and phosphates. A removal of this gangue is effected by adding lime-stone in the charge, which acts as flux. Limestone decomposes to give CaO (quick lime) 3.Zone of slag formation By Freya Cardozo

86. Zone of fusion MnO 2 and Ca 3 (PO 4 ) 2 present in the iron ore are reduced to Mn and P. Some of the silica is also reduced to Si. The spongy iron coming down in the furnace melt absorbs impurities like C, Si, Mn , P and S. This molten iron collects at the bottom in the furnace. The slag which is lighter floats on the surface of molten iron. Molten slag and iron are collected through separate outlets. Molten iron is poured into moulds. These solid blocks are called pigs. This iron contains about 4% of carbon. When pig iron is remelted , run into moulds and cooled, it becomes cast iron. The waste gases containing N 2 , CO and CO 2 escape through the outlet at the top. These hot gases are used for preheating the blast of air By Freya Cardozo

87. Zones of Blast furnace By Freya Cardozo

88. Factors affecting extraction technique Pure iron can be obtained by electrolytic refining of impure iron or other methods given in the flow chart. The choice of extraction technique is governed by the following factors. 1. Nature of ore 2. Availability and cost of reducing agent, generally cheap coke is used 3 . Availability of hydraulic power. 4. Purity of product (metal) required. 5 . Value of byproducts for example, SO 2 obtained during roasting of sulphide ores is vital for manufacture of H 2 SO 4 . Knowledge of electrochemical series provides solutions to many problems. By Freya Cardozo

89. TYPES OF IRON By Freya Cardozo

90. By Freya Cardozo THANKYOU