Which forms coloured salts
Metals
Non-metals
$p -$ block elements
Transitional elements
The number of unpaired electrons in $M{n^{ + 3}}$ is
Cuprous ion is colourless while cupric ion is coloured because
The catalytic activity of the transition metal and their compound is due to their
Although $Zr$ belongs to $4d$ and $Hf$ belongs to $5d$ transition series but it is quite difficult to separate them. Why ?