A first row transition metal with highest enthalpy of atomisation, upon reaction with oxygen at high temperature forms oxides of formula M_2 O_n…

A first row transition metal with highest enthalpy of atomisation, upon reaction with oxygen at high temperature forms oxides of formula $\displaystyle \mathrm{M}_2 \mathrm{O}_{\mathrm{n}}$ (where $\displaystyle \mathrm{n}=3,4$, $\displaystyle 5$). The 'spin-only' magnetic moment value of the amphoteric oxide from the above oxides is $\displaystyle \_\_\_\_$ BM (near integer) (Given atomic number : $\displaystyle \mathrm{Sc}: 21, \mathrm{Ti}: 22, \mathrm{~V}: 23, \mathrm{Cr}: 24, \mathrm{Mn}: 25, \mathrm{Fe}: 26, \mathrm{Co}: 27$, $\displaystyle \mathrm{Ni}: 28, \mathrm{Cu}: 29, \mathrm{Zn}: 30$ )