Which of the following contain $'Sn'$ metal

Which of the following ions has the highest magnetic moment

A pink coloured salt turns blue on heating. The presence of which cation is most likely ?

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 catalytic activity of the transition metals and their compounds is ascribed to their

The Azimuthal quantum number for the valence electrons of $\mathrm{Ga}^{+}$ion is $.....$

(Atomic number of $\mathrm{Ga}=31$ )