Chloro compound of vanadium has only spin magnetic moment of $1.73\, BM$. This vanadium chloride has the formula:

Calculate the magnetic moment of a divalent ion in aqueous solution if its atomic number is $25$

Transition metals show paramagnetism

Ferrous sulphate on heating gives

A first row transition metal with highest enthalpy of atomisation, upon reaction with oxygen at high temperature forms oxides of formula $\mathrm{M}_2 \mathrm{O}_{\mathrm{n}}$ (where $\mathrm{n}=3,4,5$ ). The 'spin-only' magnetic moment value of the amphoteric oxide from the above oxides is. . . . . . ..$\mathrm{BM}$ (near integer)

(Given atomic number: $\mathrm{Sc}: 21, \mathrm{Ti}: 22, \mathrm{~V}: 23$, $\mathrm{Cr}: 24, \mathrm{Mn}: 25, \mathrm{Fe}: 26, \mathrm{Co}: 27, \mathrm{Ni}: 28, \mathrm{Cu}: 29$, $\mathrm{Zn}: 30)$

Which of the following statements are correct about $Zn,\,Cd$ and $Hg$ ?

$(I)$ they exhibit high enthalpies of atomisation as the $d-$ subshell is full

$(II)$ $zn$ and $Cd$ do not show variable oxidation states while $Hg$ shows $+ I$ and $+ II$

$(III)$ Compound of $Zn,\,Cd$ and $Hg$, are paramagnetic in nature

$(IV)$ $Zn,\,Cd$ and $Hg$ are called soft metals