Question

Among cobalt rohodium and pt and cu which are typical transition element

Answer 1

Metallic Fe and Co and Fe- and Co-based oxide nanoparticles were prepared by a novel method utilizing the biologically relevant protein ferritin. In particular, iron and cobalt oxyhydroxide nanoparticles were assembled within horse spleen and Listeria innocua derived ferritin, respectively, in the aqueous phase. Ferritin containing either Fe or Co oxide was transferred and dried on a SiO2 support where the protein shell was removed during exposure to a highly oxidizing environment. It was also shown that the metal oxide particles could be reduced to the respective metal by heating in hydrogen. X-ray photoelectron spectroscopy was used to characterize the composition of the particles and atomic force microscopy was used to characterize the size of the nanoparticles. Depending on the Fe or Co loading and/or type of ferritin used, metallic and oxide nanoparticles could be produced within a range of 20−60 Å.

Answer 2

Transition elements are those elements which have incompletely filled d-orbitals in its ground state or in any one of its oxidation states .
Coinage metals belong to group 11. Pd , Ag , Cu and Au are regarded as transition metals because they have incompletely filled d-orbitals in its ground state or one of its oxidation state. Zinc , cadmium and mercury belong to group 12 and they have full d10 configuration in its ground state as well as in their common oxidation states. Therefore , they do not show the properties of typical transition metals as their chemistry revolves more around the s-electrons and therefore show some properties of s-block elements.