Calculate the 'spin only' magnetic moment of $M ^{2+}(\operatorname{aq})$ ion $(Z=27)$
$Z=27$
$\Rightarrow[ Ar ] 3 d^{7} 4 s^{2}$
$\therefore M^{2+}=[A r] 3 d^{7}$
i.e., $3$ unpaired electrons
$\therefore n=3$
$\Rightarrow \sqrt{n(n+2)}=\mu$
$\Rightarrow \sqrt{3(3+2)}=\mu$
$\Rightarrow \sqrt{15}=\mu$
$\mu \approx 4 \,BM$
Many transition metals form interstitial compounds. The characteristics of these interstitial compounds are
$(I)$ They have high melting points, higher than those of pure metals
$(II)$ They are very hard
$(III)$ They retain metallic conductivity
$(IV)$ They are chemically more reactive than the pure metals
The correct order of the first ionization enthalpies is
Mercury is a liquid at $0\,^o C$ because of
Which of the following is $NOT$ a characteristic of the transition elements in the series from scandium to zinc?
Which of the following $3 d -m e t a l$ ion will give the lowest enthalpy of hydration $(\Delta_{ hyd } H )$ when dissolved in water?