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Can we detect fake notes using lanthanides? Can we detect fake notes using lanthanides? Lanthanide ions such as Eu+3, Tm+3 and Tb+3 show chemiluminiscence when combined with certain organic molecules like 2‐hydroxyisophthalamide and 1‐hydroxypyridin‐2‐one. These luminescent lanthanide complexes can be used for making luminescent synthetic fibers. These polymers have wide variety of applications in industry. Synthetic fibers made luminescent using a Europium(III) complex are present in certain Euro bank notes. When you hold these notes under an ultraviolet lamp, you will see the typical red glow from europium complexes. If the bank note is fake you won't observe this luminescence.

Learning Objectives

After completing the topic, the student will be able to:

  • List the f‐block elements, classify them into lanthanides and actinides.
  • Write their electronic configurations of lanthanides and actinides.
  • Describe the extraction methods of lanthanides and actinides.
  • Give various separation methods of lanthanides.
  • Distinguish between lanthanides and rare earth elements.
  • Discuss the general physical and chemical properties of inner transition elements.
  • Compare the properties of transition and inner transition elements.
  • Examine the difference in behavior of lanthanides and actinides.
  • Give the uses and applications of f–block elements and their compounds.
The building up principle Inner transition group in periodic table The block of elements in the periodic table consisting of the lanthanoid series and the actinoid series
F-block periodic table
f-block Elements

The f‐block of the periodic table consists of those elements whose atoms or ions have valence electrons in f‐orbitals. Actual electronic configurations may be slightly different from what is predicted by the Aufbau principle.

F‐block elements are also termed as inner transition elements as they are transition elements within the transition elements i.e., d‐block elements.

Classification of f‐block elements: Depending upon whether the last electron enters a 4f orbital or a 5f orbital, the f‐block elements have been divided into two series:
Lanthanide series (15 elements from lanthanum to lutetium)
Actinide series (15 elements from actinum to lawrencium)

For semantic reasons, the Lanthanides (with the exception of lutetium) and Actinides (with the exception of lawrencium) are shown as two additional rows horizontally below the main periodic table. Otherwise it would stretch too long!

Periodic table The building up principle The electron configuration or organization of electrons orbiting neutral atoms shows a recurring pattern or periodicity. The electrons occupy a series of electron shells (numbered shell 1, shell 2, and so on). Each shell consists of one or more sub‐shells (named s, p, d, f and g). Using the principle, electronic configuration of "La"(Z=57) would be 1s22s22p63s23d104s24p64d105s25p65d106s2
No. of Lanthanides/Actinides – 14 or 15 ?
Lanthanides

The elements in which the last electron enters one of the 4f orbitals are called 4f‐block elements or first inner transition series. These are also called lanthanides or lanthanons. The symbol Ln is used informally to refer to any of the Lanthanide. The first 14 elements belong to f-block while lutetium alone is a d‐block element. Lutetium (Lu) is also considered to be a lanthanide as it has similar chemical properties.

Actinides:
The elements in which the last electron enters one of the 5f orbitals are called 5f‐block elements or second inner transition series. These are also called actinides or actinons or actinoids. These actinoids are radioactive in nature and lie below the lanthanides