Nitrogen gas is absorbed by which of the following substances at high temperature to form a cyanamide derivative?

The order of catenation power is $Ge < Si < C$. What are the $C-C$,$Si-Si$,and $Ge-Ge$ bond energies (in $kJ/mol$) respectively?

The three elements $X$,$Y$ and $Z$ with electronic configurations shown below all form hydrides:

Element	Electronic configuration
$X$	$1s^2, 2s^2, 2p^2$
$Y$	$1s^2, 2s^2, 2p^6, 3s^1$
$Z$	$1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 3d^{10}, 4s^2, 4p^5$

Which set of properties match correctly with properties of the hydrides of these elements?

At high temperature,nitrogen combines with $CaC_2$ to give:

Which of the following properties is not correct for silicones?

Which property of $CO_2$ makes it biologically and geo-chemically important?