The composition of 'Golden spangles' is

Identify the elements of alkali metals and alkaline earth metals respectively having the highest $1^{st}$ ionization enthalpy.

Which of the following compounds decompose on heating?

The pair$(s)$ of reagents that yield paramagnetic species is/are:
$A$. $Na$ and excess of $NH_3$
$B$. $K$ and excess of $O_2$
$C$. $Cu$ and dilute $HNO_3$
$D$. $O_2$ and $2-ethylanthraquinol$

The alloy used in the construction of aircraft is

The correct statements among the following are:
$(A)$ $BeH_2$ and $MgH_2$ are polymeric in nature.
$(B)$ $LiH$ is unreactive to oxygen at moderate temperatures.
$(C)$ $BeH_2$ and $MgH_2$ possess significant covalent character.
$(D)$ The stability of alkali metal hydrides follows the order $LiH < NaH < KH < RbH < CsH$.