d and f-Block Elements

• The d-block occupies groups 3-12 in the periodic table
• F-block elements fill the 4f and 5f orbitals and are placed at the bottom of the periodic table
• Transition metals and inner transition metals are other names for d and f-block elements respectively

Transition Metals

• Include 3d series (Sc to Zn), 4d series (Y to Cd), 5d series (La and Hf to Hg), and the 6d series (Ac and Rf to Cn)

Inner Transition Metals

• Include 4f series (Ce to Lu) known as Lanthanoids and 5f series (Th to Lr) known as Actinoids
• Transition metals got the name because their chemical properties are transitional between s and p-block elements
• Transition metals involve metals with incomplete d subshells in either their neutral atom or ions
• Zinc, cadmium, and mercury of group 12 with a full d¹⁰ configuration are not regarded as transition metals
• Studying the chemistry of the end members of the 3d, 4d and 5d transition series along with the chemistry of the transition metals
• Partly filled d or f orbitals distinguish transition elements from non-transition elements

Electronic Configuration

• The general electronic configuration of the outer orbitals is (n-1)d¹⁻¹⁰ns¹⁻² except for Pd which has 4d¹⁰5s⁰
• The inner d orbitals may have one to ten electrons and the outermost ns orbital may have one or two electrons
• Because of the energy difference between (n-1)d and ns orbitals, there are exceptions like Cr and Cu in the 3d series
• Cr has a 3d⁵4s¹ configuration instead of 3d⁴4s²
• Cu has a 3d¹⁰4s¹ configuration instead of 3d⁹4s²

Metallic Properties

• Transition elements generally display typical metallic properties
• This includes high tensile strength, ductility, malleability, high thermal and electrical conductivity and metallic lustre
• Zn, Cd, Hg and Mn are an exception, where they have typical metallic structures at normal temperatures
• The transition metals (except Zn, Cd and Hg) are very hard with low volatility
• The high melting points are attributed to the involvement of greater number of electrons, from (n-1)d in addition to the ns electrons in the interatomic metallic bonding
• Melting points rise to a maximum at d⁵ except for Mn and Te
• All melt points then fall regularly as the atomic number increases
• High enthalpies of atomisation increase with unpaired electrons
• Metals of the second and third series have greater enthalpies of atomisation than the first series, this accounts for metal-metal bonding in the heavy transition metals

Atomic and Ionic Size Variation

• For ions of the same charge, radius decreases with increasing atomic number
• The general decrease happens because new electrons enter a d orbital while nuclear charge increases
• The shielding effect a d electron is not effective, which increases net electrostatic attraction, and decrease ionic radius
• The variation within a series is small
• Atomic sizes show an increase from the first (3d) to the second (4d) series
• Radii of the third (5d) series are about the same as the second (4d) series due to lanthanoid contraction
• Lanthanoid contraction, due to the filling of 4f orbitals, cancels the expected increase in atomic size
• Lanthanoid contraction involves imperfect shielding that one 4f electron has on another
• Decreases in metallic radius with atomic mass increase the density of the elements
• Density increases significantly from titanium (Z = 22) to copper (Z = 29)

Ionisation Enthalpies

• There is an increase in ionisation enthalpy from left to right
• This is due to the filling of the inner d orbitals, which increases nuclear charge
• The increase of successive enthalpies of these elements is not as steep as with non-transition elements
• Removing one 4s electron influences the relative energies of the 4s and 3d orbitals
• The atomic radii decrease slowly
• This means ionization energies increase only slightly along the 3d series
• Doubly or more highly charged ions lack 4s electrons
• Second ionisation enthalpy increases the effective nuclear charge with one d electron does not shield another electron because their orbitals differ in direction
• Steadily increasing second and third ionisation enthalpy trends break for stable Mn²⁺ and Fe³⁺ ions
• Attraction towards nucleus, repulsion between electrons, as well as exchange energy determine ionisation enthalpy
• Exchange energy stabilizes the energy state
• There is no loss of exchange energy at d⁰ configuration
• The lowest common oxidation state of the metals is +2
• Dominated by requires the second ionisation enthalpy and the enthalpy of atomisation.
• High values for Cr and Cu occurs due to M+ ions
• High values for third ionisation enthalpies indicates why oxidation state greater than two is hard to produce

Oxidation States

• One feature of transition elements is the large variety of oxidation states exhibited
• The greatest number of oxidation states are found in the middle
• Fewer electrons to lose or share at the the extreme ends (Sc, Ti)
• Too many d electrons for higher valency at the other extreme ends (Cu, Zn)
• Scandium(II) is virtually unknown and titanium (IV) is more stable
• Zinc only shows an oxidation state of +2 (no d electrons)
• Reasonable stability reaches the sum of the s and d electrons upto manganese followed by an abrupt decrease in stability of higher oxidation states
• The varying oxidation states are due to incomplete filling of d orbitals
• Varying oxidation states differ by one
• The lower oxidation states favor heavier elements in the p block, but the opposite is true in the d block
• Mo(VI) and W(VI) are more stable than Cr(VI)
• Complex compounds with ligands have pi-acceptor character for low oxidation states
• Examples include Ni(CO)₄ and Fe(CO)₅, where oxidation state is zero

Chemical Reactivity and Electrode Potential

• Transition metals vary in reactivity, often dissolving in mineral acids
• Some are considered noble and unaffected by single acids
• Metals, except copper, are more reactive and oxidisable by 1M H⁺
• Electrode potential values indicate a decreasing tendency to form divalent cations
• Electrode potential values for Mn, Ni, and Zn are more negative
• The stabilities of half-filled d and completely filled d subshells are important for the electrode potential
• Mn³⁺ and Co³⁺ ions are strong oxidising agents while Ti²⁺, V²⁺, and Cr²⁺ are strong reducing agents

Magnetic Properties

• Diamagnetism and paramagnetism are two kinds of magnetic behavior observed in substances
• Diamagnetic substances are repelled by a field but Paramagnetic substances are attracted
• Paramagnetism comes from unpaired electrons, with each electron possessing a magnetic moment
• For the first series, orbital angular momentum is quenched. Here, the magnetic moment relies on unpaired electrons
• A single unpaired electron carries a magnetic moment of 1.73 Bohr magnetons (BM)
• Magnetic moment values show the number of unpaired electrons in an atom, molecule, or ion

Formation of Coloured Ions

• When an electron in a lower energy d orbital gains frequency energy it boosts to a higher energy d orbital
• The frequency of excitation corresponds to light absorbed, and complements the color you can observe
• The ligand's physical traits impacts frequency of light absorbed
• Due to electrons filling in the f level, lanthaniod ions have shown to be coloured
• Other than f⁰ or f¹⁴, the other elements are paramagnetic

Complex Compounds

• Complex compounds are when metal ions bond to any number of neutral molecules to give characteristics
• Examples include [Fe(CN)₆]³⁻, [Fe(CN)₆]⁴⁻, [Cu(NH₃)₄]²⁺ and [PtCl₄]²⁻

Catalytic Properties

• Transition metals have catalytic abilities because they can adopt multiple oxidation states and create complexes
• Vanadium(V) oxide (Contact Process), finely divided iron (Haber's Process) and nickel (Catalytic Hydrogenation) are examples
• Catalysts at a solid surface create bonds between reactant molecules and the catalyst surface atoms
• Transition metal ions change their oxidation

Formation of Interstitial Compounds

• Small atoms such as H, C or N are trapped inside the crystal lattices of metals, compounds referred to as interstitial
• Typically non stoichiometric and not typically ionic or covalent (ie TiC, Mn4N, Fe3H, VH0.56 and TiH1.7)
• Interstitial compounds have high melting points, are very hard, are metallic conductive, and chemically inert

Alloy Formation

• Alloy is a mixture of metals combined together, in which Atoms of the metal in a solution randomly spread out among other atoms
• Alloys feature atoms within 15% of their metallic
• Alloys become very strong with high melting points
• Types of alloys includde ferrous alloys, and also brass (copper-zinc) and bronze (copper-tin) alloys have industrial importance

Oxides and Oxoanions of Metals

• Oxides are typically formed by having metals react with oxygen at high temperatures
• Oxides besides scandium have the formula MO
• Sc groups up to Mn form the highest oxidation number coincides where oxides exist
• Other than oxides, oxocations can stabilise V, Ti

Potassium dichromate K2Cr2O7

• Potassium dichromate, K2Cr2O7, is useful for the leather industry as well as oxidant when making azo compounds
• Sodium and potassium carbonates fuse chromite ore (formula FeCr2O4) to create dichromates
• Reaction with sodium carbonate: 4 FeCr2O4 + 8 Na2CO3 + 7 O2 → 8 Na2CrO4 + 2 Fe2O3+ 8 CO2

Potassium Permanganate KMnO4

• To make potassium permanganate, fuse MnO2 with alkali metal hydroxide and oxidizing agent like KNO3
• This produces dark green K2MnO4 that disproportionates in neutral or acidic
• Also made by oxidizing alkaline form MnO2, which forms manganate oxidization

Oxidation of permanganate

• The higher hydrogen concentration, the stronger reactions may occur
• Permanganate at [H⁺] = 1 should oxidize water, however such reaction is slow, requires prescence of Mn(II) ions, higher temperatures
• reactions include Iodine is liberated from potassium iodide, Fe²⁺ ion (green)) is converted to Fe³⁺ (yellow)

Inner transition Elements (f-Block)

• F-Block's make up are with Lanthanoids , fourteen following lanthanum
• Actinoids contain the fourteen elements after the actiniun
• Lanthanoids all have only a single stable oxidation with excellent opportunity examine affect of varying nuclear charged
• Chemistry with actinoids more complicated since they have wider range of oxidation yet radiocactivity yields study difficulties
• Names, sums atom/ionic radius of electron configurations lanthanium and lanthiniods outlined table 8.9

Electronic Configurations

• Most of these atoms show some form of variable occupancy, especially among 4f subshells
• Regardless, the triple positive form all ions are fⁿ from one to 14, in line with the atomic number

Actinic Contraction

• From lanthanum to lutetium, the decreasing size of ionic and atomic radii is a feature distinct chemical
• This can go on impact general nature third trans series of the element
• Atomic mass is quite irregular, with atomic radii steadily shrinking
• That shielding one election from others is weaker when atomic numbers increase
• Due to contraction, virtually iddentitcal radio activity, elements occur at same time and struggle separate

Oxidation States

• La(II) and Ln(III) compounds form predominately
• Undergo +2, +4 oxidization for stability among orbitals
• Ce, which can oxidate water
• Pr, Nd,Tb, and Dy oxidise in oxides however
• E, forms from lising pairs of electrons
• Yb, also a reductant has f14 configuration

General Characteristics

• Many lanthanides present as silver or metal that's soft and tarnishes
• The melting points span from thousands to twelves hundreds if measured in kelvin
• Ions from lanthanoids can take shape colored solids or solute aquatic
• Absorption levels probably attributed presence f electrons

Trends in Reactivity

• Early series display high Reactivity such as calcium
• Atomic number rises, series can act like alluminum
• Reaction: Ln³(aq) + 3e ⁻ → Ln(s)
• These range in measurement from negative 2.2-2.4V mostly at -2.0v
• Some also include nitrogen , carbon which form carbides then will dilute with other stuff

Actinoids

• Includes elements with atomic numbers between to 89 to 103 following Actiniums
• All have electronic setup as 7s to occupy shell while the form in orbitals 5f orbital-wave function
• Trend is similar Lanthanides but contractions greater as shielded
• Energy amounts and levels are comparable
• Actinoids show third state while their initial element is frequently higher
• display unequal distribution

General and comparison of lanthonoids

• All actinoid metals display structural differenties attributed irrégularités in metal radii . Actinoids are highly sensitive metals or mixtures oxides combine with water and nonmetals during temperature peaks
• Though many properties align, actinoid's and Lanthanide's properties deviate
• Much lower ionization enthalpies though
• Lanthanoid and actinoid reactions stretch over lengths properties become less significant