How does the ionization energy of the elements of Group $1$ change as we move down the group?

In the presence of which of the following does magnesium continue to burn?

Magnesium liberates $H_2$ gas on reaction with

Identify $X$ and $Y$, respectively in the following reactions:

State True or False:
$(1)$ Half-life of $^{223}Fr$ is $21 \ s$.
$(2)$ $Li^{+}$ has a high hydration enthalpy and therefore its salts are usually hydrated in nature.
$(3)$ Among all the alkali metals,only $Na$ can react with nitrogen of air and form a nitride.
$(4)$ Except $LiF$,other halides of $Li$ are soluble in water.

Which of the following metals releases hydrogen gas upon reaction with cold and dilute $HNO_3$?