In the periodic table actinides occupy :
III B group in 7th row
III B group in 6th row
III B group in 5th row
None of the above
Why Sc (Z = 21) is not considered as transition element ?
Properties of Sc are similar to alkali metals
3d - orbitals are empty in its stable compound
Stable oxidation number of Sc is +2
Atomic volume of Sc is very large
The properties of Zr and Hf are same because :
they have similar radii
they belong to d-block
they have same valence electrons
None of the above
A.
they have similar radii
It is because of lanthanide contraction due to which ionic radii of second and third transition series are same , thus , properties of Zr and Hf are same as they have similar radii .
Zr4+ (40) 79 pm
Hf4+ (72) 78 pm
Formation of coloured solution is possible when metal ion in the compound contains :
paired electrons
lone pair of electrons
unpaired electrons
None of the above
In the periodic table metals usually used as catalysts belong to :
f - block
d - block
p - block
s - block
In a neutron induced reaction of , the product obtained is , three neutrons and an element (new nuclide) .The other new nuclide is :