Chemistry > d and f Block Elements > 7.0 Lanthanoid Series
d and f Block Elements
1.0 General Introduction and Electronic Configuration
2.0 Occurrence and General Characteristics of Transition Elements
3.0 General Trends in properties of First Row Elements
3.1 Ionisation Enthalpy
3.2 Oxidation State
3.3 Atomic and Ionic Radii
3.4 Colour
3.5 Catalytic properties
3.6 Magnetic Properties
3.7 Formation of Interstitial Compounds
3.8 Alloy Formation
4.0 Potassium dichromate
5.0 Potassium permanganate
5.1 Properties of potassium permanganate
5.2 Structure of manganate ion and permanganate ion
5.3 Disproportion of an oxidation state
5.4 Uses
6.0 F-Block Elements - Introduction
7.0 Lanthanoid Series
7.1 Position of Lanthanoid Series
7.2 Electronic configuration of lanthanoids
7.3 Oxidation States
7.4 Chemical Reactivity of Lanthanides
8.0 Lanthanoid Contraction and its consequence
9.0 Actinoids Series
9.1 Position of Actinoids in periodic table
9.2 Electronic Configuration of actinoids
9.3 Oxidation states of actinoids
10.0 Comparison between lanthanoids and actinoids
7.2 Electronic configuration of lanthanoids
3.2 Oxidation State
3.3 Atomic and Ionic Radii
3.4 Colour
3.5 Catalytic properties
3.6 Magnetic Properties
3.7 Formation of Interstitial Compounds
3.8 Alloy Formation
5.2 Structure of manganate ion and permanganate ion
5.3 Disproportion of an oxidation state
5.4 Uses
7.2 Electronic configuration of lanthanoids
7.3 Oxidation States
7.4 Chemical Reactivity of Lanthanides
9.2 Electronic Configuration of actinoids
9.3 Oxidation states of actinoids
Name of elements | Symbol | At. No. | Observed (actual) configuration | Name of elements | Symbol | At. No. | Observed (actual) configuration |
Lanthanum | La | 57 | ${[Xe]_{54}}4{f^0}5{d^1}6{s^2}$ | Terbium | Tb | 65 | ${[Xe]_{54}}4{f^9}5{d^0}6{s^2}$ |
Cerium | Ce | 58 | ${[Xe]_{54}}4{f^2}5{d^0}6{s^2}$ | Dysprosium | Dy | 66 | ${[Xe]_{54}}4{f^10}5{d^0}6{s^2}$ |
Praseodymium | Pr | 59 | ${[Xe]_{54}}4{f^3}5{d^0}6{s^2}$ | Holmium | Ho | 67 | ${[Xe]_{54}}4{f^11}5{d^0}6{s^2}$ |
Neodymium | Nd | 60 | ${[Xe]_{54}}4{f^4}5{d^0}6{s^2}$ | Erbium | Er | 68 | ${[Xe]_{54}}4{f^12}5{d^0}6{s^2}$ |
Promethium | Pm | 61 | ${[Xe]_{54}}4{f^5}5{d^0}6{s^2}$ | Thullium | Tm | 69 | ${[Xe]_{54}}4{f^13}5{d^0}6{s^2}$ |
Samarium | Sm | 62 | ${[Xe]_{54}}4{f^6}5{d^0}6{s^2}$ | Ytterbium | Yb | 70 | ${[Xe]_{54}}4{f^14}5{d^0}6{s^2}$ |
Europium | Eu | 63 | ${[Xe]_{54}}4{f^7}5{d^0}6{s^2}$ | Lutetium | Lu | 71 | ${[Xe]_{54}}4{f^14}5{d^1}6{s^2}$ |
Gadolinium | Gd | 64 | ${[Xe]_{54}}4{f^7}5{d^1}6{s^2}$ |
Electronic Configuration of lanthanoids are as follows:
- The electronic configuration of nearest noble gas element $Xe$ is ${}_{54}[Xe] - 1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}4{s^2}3{d^{10}}4{p^6}5{s^2}4{d^{10}}5{p^6}$
- Atomic No.of $Ba$ is $56$ in which $6s$ is completely filled and after Barium i.e.,from lanthanum and onwards filling of $4d$ orbitals starts.
- General valence shell electronic configuration of Lanthanoids is $[Xe]4{f^{1 - 14}}5{d^{0 - 1}}6{s^2}$.
- From spectral analysis it was observed that their is a slight deviation in observed electronic configuration from idealized electronic configuration.
- In observed electronic configuration of Lanthanoids one electron from $5d$ is shifted in $4f$ except in case of $La$, $Gd$ and $Lu$.
- Electronic configuration of $Ba$ is $[Xe]6{s^2}$.
- Electronic configuration of lanthanum $[Xe]4{f^0}5{d^1}6{s^2}$ and not as $[Xe]4{f^1}5{d^0}6{s^2}$ due to empty stability of $4f$.
- After lanthanum last electron is not entering in $5d$ but in $4f$.
- As the atomic number increases addition of electrons can take place in $4f$ one by one.
- One unpaired electron is found in $5d$ of $La$, $Gd$ and $Lu$ where as in other elements $5d$ is empty.
- ${f^0},{f^7} and {f^{14}}$ have extra stability due to empty half filled and completely filled $f$-orbitals.
- This $4f$ electrons in pre-penultimate i.e., $(n-2)$ shell are totally shielded by higher outer orbital.
