What is the total number of unit cells shared by each corner particle of bcc unit cell?

Which of the following is used as reagent in Etard reaction?

For a certain reaction, $\Delta \mathrm{H}=-210 \mathrm{~kJ}$ and $\Delta \mathrm{S}=-150 \mathrm{~kJ} \mathrm{~K}^{-1}$ Find the temperature so that $\Delta \mathrm{G}=0$.

Which of the following elements contains maximum number of unpaired electrons?