Answer the following :
(a) Name of the element not known at time of Mendeleev.
(b) Name any two typical elements.
(c ) Name any two bridge elements.
(d) Name two pairs showing diagonal relationship.
(e) Name two transition elements.
(f) Name two are rare earth elements.
(g) Name two transuranic elements.
(h) In which case compounds of `Cr` show maximum radius.
(i) `K_(2)CrO_(7)`, (ii) `CrO_(2)Cl_(2)` , (iii) `Cr_(2)(SO_(4))_(3)`
(iv) `CrCl_(2)`