Which of the following non-metals has half the atomicity of sulfur?

Which one of the following elements reacts with steam?

The catenation tendency of $C$,$Si$ and $Ge$ is in the order $Ge < Si < C$. The bond energies (in $kJ \ mol^{-1}$) of $C-C$,$Si-Si$ and $Ge-Ge$ bonds,respectively,are:

Among the following oxides,which one is weakly basic and yet a powerful oxidant?

Which one of the following phosphorus halides contains both tetrahedral and octahedral shaped ions in its solid state?

What is meant by $Tin \ Cry$?