The ability to form complex compounds by the transitional metal ion is due to
Small size
Vacant $'d'$ orbitals
High nuclear charge
All of these
The colour of ${(N{H_4})_2}S{O_4}Fe{(S{O_4})_3}.24{H_2}O$ is
$Zn$ and $Cd$ metals do not show variable valency because
Properties common to the elements manganese, iron, cobalt, nickel and copper include the ready formation by them all of
$(I)$ coloured ions in aqueous solution
$(II)$ oxides of nitrogen are formed on reaction with concentrated $HNO_3$
$(III)$ chlorides of formula $MCl_2$ and $MCl_3$
The correct order of density is
Which of the following statement(s) is(are) correct with reference to the ferrous and ferric ions