D or F Block Elements Class 12 Notes 2022

(1) Elements whose electrons are filled in the D orbital are called D block elements.

(2) Elements of D block are present between S block and P block elements in the periodic table, hence the elements of D block are called transition elements.

(3) Not all elements of D block are transition metal elements but all transition metal elements are elements of D block

(4) Four categories of elements of D block are present in the periodic table.

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(5) Common electron of the elements of D block element (n-1)d{1-10}(ns){1-2}
[n = last shell]

Note – Due to very small difference in energy O of ns and (n-1)d orbitals of D block elements, many exceptions are seen in their electron configuration.

-:- 3D Series :-

This range is from 21SC to 30ZN
The electron configuration of the 3D series (inert gas (n-1)d{1-10}(ns){1-2} ) is

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4D series electron configuration :-

This series ranges from 39Y to 48Cd
Electron configuration of this series (n-1)d{1-10}(ns){1-2} n=5
(3,6,9 is the exception)

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Electron configuration of 5D series :- This series is from Lanthanum(57L) to Hg(80Hg)
This range contains elements of the 4F block from 58 to 71.

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Electronic configuration of 6D series :- This series starts from Ac (89) to Uub (112) atomic number 90 in this series. Elements from to 103 lie in between the elements of F block. This is an incomplete series.

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Characteristics of Transition Elements :- The properties which identify the transition elements are called characteristic properties.
it is the following
(1) show variable oxidation state

(2) There is a tendency to form colored compounds

(3) Tendency to form paramagnetic compound

(4) Tendency to form alloys

(5) Tends to form complex compounds

(6) These metals are used as catalysts (have catalytic properties)

General properties of transition element :-

(A) Melting Point :-

(1) The unpaired electrons present in the outermost shell of a metal element participate in the formation of metallic bonds, the more number of paired electrons present near the metal atom, the stronger the metallic bond will be formed by that metal, so that the melting point of the metal will also be higher. will be high.

(2) The unpaired electrons of (n-1)d along with ns electrons of transition metal elements also participate in forming metallic bonds, thus more number of metallic bonds are formed by a transition metal element, that is why transition metals Elements have very high melting points

(3) On moving from left to right in a series, the melting point increases till the middle and then decreases and the last element of the series has the lowest melting point, this is because the number of unpaired electrons increases till the middle of the series and decreases thereafter. looks like

(4) The melting point of mn in the 3d series is much lower than expected because the configuration of Mn is half-completed i.e. 3d5 is 4s2. As this configuration becomes stable, the contribution of electrons to the d orbitals in forming metallic bonds is reduced. The melting point of Mn is lower than expected

(5) Cr has the highest melting point in the 3d series, Zn has the lowest melting point

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(6) All metal elements tungsten (w) has the highest melting point and mercury (Hg) has the lowest melting point.

Q – 5 Why do have the lowest melting points in their respective categories?
Ans –  The configuration of Zn, Cd, and Hg is permanent that is completely complete, in which the atom does not have unpaired electrons, so very weak metallic closure is formed by these atoms, that is why Zn in their respective series. , Cd, and Hg have minimum melting points

Note – Due to low melting point of Zn, Cd, and Hg these metals have the property of volatile.

(1) On moving from left to right in a transition series, the atomic radius decreases almost to the middle, then remains constant and finally increases

(2) Generally, the value of atomic radius decreases continuously as the elements move from left to right in a period.

(3) The value of atomic radius in the transition series is determined by both nuclear charge and shielding effect

(4) The shielding effect also increases as the number of electrons in the terminal shell increases.

(5) On moving from Sc to Cr in the 3d series, the number of electrons in the d orbital increases very little, that is, the shielding effect is less, in comparison to this, the nuclear charge increases continuously, hence the atomic radius from Sc to Cr decreases.

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(6) On moving from Cr to Ni in the 3d series, the number of electrons in the d orbital increases and the shielding effect also increases, which balances the increasing nuclear charge, so the shielding effect and nuclear charge from Cr to Ni become equal. which keeps the atomic radius constant

(7) In the last shell of the 3d series, the orbitals of Cu and Zn are completely completed, due to which the shielding effect becomes more than the nuclear charge, due to which the atomic radius also increases.

Q – 6 Atomic radius increases on going from 3d series to 4d series but on moving from 4d series to 5d series the atomic radius remains constant why?
Ans – On moving from 3d to 4d, the number of a shell increases, due to which the value of atomic radius also increases It is that f electrons suddenly come in the terminal shell of 5d series, whose shielding effect is less, due to which the nuclear charge increases, due to which the value of the force of attraction of the nucleus on its electron is more at last, due to which the atomic radius remains constant.

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Q – 11 Why is the +3 oxidation state more stable than the +2 oxidation state of Fe?
Ans –

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In the +3 oxidation state of Fe, when the fe configuration is half-filled, which is a stable configuration, so the Fe+3 oxidation state is more stable than +2

Q – Why +4 oxidation state of 12* Ti is more stable than +3 why?
Ans –

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Its configuration in +4 state of Ti is stable inert gas configuration, hence +4 oxidation state is more stable than +3

Q – 13* Cr+2 is a reducing agent while Mn+3 is an oxidising agent although both have d4 configuration?
Ans – Losing electrons > Oxidation > Reducing
electron capture > reduction > oxidising agent

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Cr+2 loses one electron and changes to Cr+3 which has a stable (t2)3 g eg 0 configuration, so Cr+2 is of reducing nature.
Mn+3 acquires an electron and changes to Mn+2 so that the configuration is half-completed, so Mn+3 is oxidising in nature.

Q – 14* Which is the strongest reducing agent between Cr+2 and Fe+2? And why?
Ans – Fe+2 loses one electron and changes to Fe+3 which has configuration 3d5 which is a stable half-filled configuration, similarly Cr+2 loses one electron and changes to Cr+3 which gives t2g3 configuration which is stable configuration is
Hence, it is clear that both Fe+2 and Cr+2 are strong reducing agents, but in aqueous solutions, the t2g3 configuration is more stable than the 3d5 configuration, due to which Cr+2 will be a stronger reducing agent than Fe+2.

Q – The +3 oxidation state of 15 Cr is relatively more stable, why?
Ans –

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In Cr+3 oxidation state, Cr forms octahedral complex compound, which has the configuration t2g3 eg0 which is a stable semi-completed configuration, so the +3 oxidation state of Cr will be more stable.

Q – 16 The lowest oxide of transition metal O is basic while the highest oxide is acidic Why?
Ans –

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ionic compound => alkaline
covalent => acidic

Metals form covalent oxides in higher oxidation states which are acidic because metal cation oxides tend to polarize negative ions more in higher oxidation states. Therefore, according to the laws of Fiance, the covalent character in the bond increases, in lower oxidation states the metal forms ionic oxides. which is basic because the metal cation in the lower oxidation state is less polarized to the anion, thus forming an ionic bond between

Q-17 Highest oxidation state is exhibited in oxanion of metals?
Ans – Due to the high electronegativity and small size of the oxidizing atom, it removes a large number of electrons from the metal, as well as the ability to form multiple bonds in oxygen, that is why it exhibits the highest oxidation state in the oxa anion of the metal. are there

Note – The oxide anion has more ability to stabilize the metal in higher oxidation state as compared to F because O forms with the metal whereas F does not.

Examples of catalytic properties of transition metal O

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To make an alloy, such a metal O is mixed and mixed so that there is a maximum difference of 15% in the atomic radius, that is, those whose atomic radii are almost the same, the transition metals form the alloy easily because the atomic radius of these metals is about is the same
like –
Cu+Zn (Brass)
Cu+Sn (Casa)
Cu+Sn+Zn (Gunmetal)
Cu+Zn+Ni (German Silver)

=> Characteristics of Alloys –

1 The hardness of an alloy is greater than that of a pure metal
The melting point of an alloy is higher than that of a pure metal
3 Alloy’s workability, conductivity, non-mearability, the tendency to rust is less than that of pure metal

(I) Tendency of transition metal O to form interstitial compounds –
In a metallic crystal of a metal, small spaces are found between the metal atoms which are called interspaces when small sized atoms like B, H, C, N, etc. If it enters, it forms interstitial compounds like TiC, Fe3H, Mn3N.

=> Features of Antrakashi Yogic –
1 These are yogic arrosymmetric
2 These compounds have high melting point and hardness
3 Formation of antrakashi yogic does not affect the reactivity of the metal

D or F Block Elements Class 12 Notes 2022 d-block elements f-block elements pdf f-block elements electronic configuration D or F Block Elements Notes Pdf

lements of D and F Block,D and F Block,D Block,F Block,3D Series,4D series electron configuration,Electron configuration of 5D series,Electronic configuration of 6D series,Write the modern definition of transition metal elements,

Why are Zn, Cd, and Hg not considered as transition elements,Why are the elements of 4 d block studied on the basis of categories,Why do the elements of d block have vertical parallelism as well as horizontal similarity,

Characteristics of Transition Elements,General properties of transition element,Melting Point,Atomic Radius,Condensation Enthalpy,Why transition metal has high particle enthalpy,Why Zn has minimum particle enthalpy in 3d series,Oxidation State,

Tendency to form complex compounds,Why are most compounds of transition metals coloured,Why Ti+4 is colourless,Magnetic properties of transition metal O,Diamagnetic substances,Paramagnetic substances,

Ferromagnetic substances,Catalytic properties of transition metals O,Tendency of transition metal O to form alloy,Characteristics of Alloys,Features of Antrakashi Yogic,Elements of P block,Electron configuration of F block,

Electron configuration of 5f series,Explain what is called lanthanide contraction,What is Ac contraction or what is called actinide contraction,What is a mish metal, tell its use,Ac contraction is greater than La contraction,