Illustrate Magnetic properties of f-block element, Chemistry

Q. Magnetic Properties of f-block element?

You have learnt in the preceding unit-that paramagnetism is related with the presence of unpaired electrons in a substance. The actinide and lanthanide ions,  other than type (e.g.  La3+, Ce4+, Ac3+, Th4+, Pa5+, U6+, and f14 type ( e, g Yb2+ Lu3+ Lr3+paramagnetic, due to each of the seven f orbitals charactering inner -transition metal  species (lanthanide and actinide) must have a single electron before any pairing can take  place (Hund's rule).

You have also studied that in case of transition elements; the contribution of orbital motion of electrons to paramagnetism is negligible and will be ignored. The magnetic moments of transition metal ions can be explained in terms of unpaired electrons present in d-orbitals.  But the magnetic moments of only those lanthanide ions, which have,f0 f7and f14 configuration agree with the spin only value. In all other cases, the magnetic moment value are higher than those evaluated on the basis of spin only formula. Though, these can be explained by taking orbital contribution to magnetic moment also into account. In lanthanide ions, the 4f orbitals are comparatively better shielded from the surroundings by the overlying 5p and 5s orbitals than the d orbitals in transition metal ions. Thus, the contribution of orbital motion to paramagnetism is not quenched. 

Although actinides show a variation in magnetic properties same to that of the lanthanides, the magnetic properties of the actinide ions are more complicated than those of the lanthanide ions. This in part arises from (i) the fact that the 5f electrons are nearer the surface of the atom and are easily influenced by the chemical environment; although not to the similar extent as do the d electrons, and (ii) the less sharply illustrate distinctions between 5f and 6d electrons as compared with 4f and 5d electrons. From the above discussion it is clear that the magnetic moments of the f-block (inner transition) metal ions have to be calculated taking into account both spin and orbital contributions.

Posted Date: 7/12/2013 6:36:40 AM | Location : United States







Related Discussions:- Illustrate Magnetic properties of f-block element, Assignment Help, Ask Question on Illustrate Magnetic properties of f-block element, Get Answer, Expert's Help, Illustrate Magnetic properties of f-block element Discussions

Write discussion on Illustrate Magnetic properties of f-block element
Your posts are moderated
Related Questions
Q. Explain: Vulcanization of rubber is necessary. Ans. Importance of vulcanization of rubber: 1.                 Vulcanization makes cross-links between the long unsaturat


For which of the following sets of four quantum numbers, an electron will have the highest energy:             n            l             m            s

Explain about the Defect breakdown It is because of cracks and pores at the surface. Moisture from atmosphere can collect on the surface and result in breakdown. Glazing is

Name the principal ore of tin or lead. Describe the different steps (along with equationsfor the reactions) involved in the extraction of the metal from the ore named. Name

Fundamentals of Acids and Bases Bronsted-Lowry theory: A Bronsted acid is a (proton) + donor, whilst a Brønsted base is a proton acceptor. An acid-base reaction involves t

methods of purification of organic compounds with diagrams ..

how caustic soda preparaed at lab scale?explain with labelled diagram?

Q. Limitations of Hybrid orbitals? It gives no idea whether a particular metal ion would prefer to have any particular geometry say, an octahedral or tetrahedral with a giv

Physical properties of Halo-arenes (i) Physical state: they are colourless liquid or crystalline solid. (ii) Solubility: Halo-arenes are not soluble with water, but dissolve