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.  La^3+, 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

Ask an Expert

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

Write your message here..

Related Questions

Periodic, where is the asterisk located where is the asterisk located

Effect of concentration, Q. Show the Effect of concentration on Chemical Eq... Q. Show the Effect of concentration on Chemical Equilibrium? Ans. When more of one of the chemicals is added to the reaction, more collisions take place moving the reactio

Sequence of amino acids histidine-glutamine-lysine in buffer, In lab, you'r... In lab, you're having fun along with buffers based onto a 0.1 M solution of sodium phosphate at pH7.0.  Into this system, there are three of pK A s as:  12.7, 7.21 and 2.12.

Matter, name any 10 chemical compound used at homewith their molecular form... name any 10 chemical compound used at homewith their molecular formula

Sketch a flow diagram of a water treatment process, Comment on each of the ... Comment on each of the raw water parameter's significance in relation to the selection of appropriate water treatment process. Sketch a flow diagram of a treatment process to pr

Kinetic energy, How might temperature changes in the human body have an imp... How might temperature changes in the human body have an impact on human health

Catalyst.., assignment assignment

Classic flame photometric experiment, Classic flame photometric experiment:... Classic flame photometric experiment: In a classic flame photometric experiment, a solution of the analyte is aspirated within the burner and dispersed into the flame as a fin

Classification of proteins - globular proteins, Globular proteins These... Globular proteins These proteins comprise more or less spherical shape (compact structure). α-helics are firmly held up by weak attractive forces of numerous types that are Hyd

General , Match the compounds below with the type of bonding each predomina... Match the compounds below with the type of bonding each predominately exhibit. Question 3 options: NaCO3 NaBr SOCl2 CH4 1. ionic bonding 2. covalent bonding