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
Coordination number and geometry   Binary compounds are ones with two different elements present. 'Simple' crystal structures can be classed as ones in which each atom (or


Q. Show the Properties of diborane? Diborane is a colourless gas (b. p., 183K). It is rapidly decomposed by water with the formation of H 3 B0 3 and H 2 : B 2 H, + 6H 2 0 -

What are molecular orbitals? How are they formed? What does molecular orbital theory states? what is the significance of molecular orbital theory? Ans) Molecular orbitals are for

OUTLINE AND EXPLAIN THE LIMITATIONS OF VBT

The number of orbitals in d  sub-shell is : (1) 1        (2) 3        (3) 5        (4) 7 Ans: 5

what is the unique properties of colloids

#What is the proof of formulae for finding Equivalent weight

1. why YbS and YbI2 are semiconducting solids but LaS and LaI2 show metallic character. 2. Why is aqueous solution of Eu2+ thermodynamically less susceptible to oxidation than any

How many grams are in 4.5 moles of carbon?