Question

12. S&Co has been used in the study of function of
body.
in the
13. Each haemoglobin molecule has
globin on its surface.
group which are bound to
14. Electronic spectra of f-block elements exhibit
bands.
15. Addition of H2 and Co to an olefin to produce an aldehyde is called
reaction.​

Answer 1

Answer:

Atomic and ionic radii of lanthanides decrease with an increase in atomic number. This gradual decrease is known as lanthanides contraction.

Because of the lanthanides contraction, the radii of the elements of the 3rd transition series are very similar to those of the corresponding elements of the 2nd transition series elements.

Oxidation States of Lanthanides

Lanthanides exhibit the oxidation state of +3. Some of them also exhibit the oxidation state of +2 and +4.

a noble gas configuration e.g. Ce4+ (f0)

a half filled f shell e.g. Eu2+ (f7)

a completely filled f shell e.g. YB22+ (f14)