Kerala Syllabus SAMAGRA SCERT SAMAGRA Question Pool for Class 12 Chemistry The d- and f- Block Elements
The general electronic configuration of transition elements is ……………
(a) (n-2)d1-10 ns 1-2 (b) nd1-10ns1-2
(c) (n-1) d1-10 ns1-2 (d) (n-1)d1-10 ns0
Account for the following.
a) The transition metals generally form coloured compounds.
b) Transition metals act as good catalyst.
c) Transition metals form alloys.
a) Presence of unpaired d electrons
b) Variable oxidation states and forms complexes.
c) Similar metallic
a) Transition metals and most of their compounds show paramagnetic behaviour. Why?
b) Find the magnetic moment in Bohr Magneton (BM) of Co2+ ion
(Hint: Outer electronic configuration of Co is 3s2 3p6 3d7 4s2)
a) Presence of unpaired d electrons.
b) μ = √n(n+2), where n – no. of unpaired d electrons.
Give reasons for the following.
(a) Transition elements have variable oxidation state
(b) The aqueous solution of Cu+ is not stable
(a) Low energy difference between (n-1)d and ns orbitals
The atomic and ionic radii of third transition series of elements show regular decrease with increasing atomic number.
(a) Name this phenomenon
(b) Explain the reason for this phenomenon and write any two consequences of it.
(a) Lanthanoid contraction
(b) Poor shielding effect of 4f orbitals filled before 5d
The outer electronic configuration of Au is 5s25p65d106s1 and that of Zn is 3s2 3p63d104s2
(a) Write the outer electronic configuration of Au2+ and Zn2+ ions
(b) Explain why Au is considered as a transition element but Zn is not
(a) Au2+ 5s25p65d9