The least reactive metal is

Amongst the following,the lowest degree of paramagnetism per mole of the compound at $298 \ K$ will be shown by:

The metal ion having maximum paramagnetic behaviour among the first transition series elements is,

$A$ chloro compound of vanadium has a spin-only magnetic moment of $1.73 \ BM$. This vanadium chloride has the formula:

Which of the following elements can form complex ions?

Although Zirconium $(Zr)$ belongs to the $4d$-transition series and Hafnium $(Hf)$ belongs to the $5d$-transition series, they show similar physical and chemical properties because . . . . . . .