Which alkali metal is most metallic in character?

Consider the following statements.
$I$. $Cs^{+}$ ion is more highly hydrated than other alkali metal ions.
$II$. Among the alkali metals,only lithium forms a stable nitride by direct combination with nitrogen.
$III$. Among the alkali metals $Li, Na, K, Rb$,the metal $Rb$ has the highest melting point.
$IV$. Among the alkali metals $Li, Na, K, Rb$,only $Li$ forms peroxide when heated with oxygen.
Select the correct statement.

Which of the following methods is generally used for the extraction of alkali metals?

$Mg$ is obtained by:

Which of the following metals is found in the green colouring pigment chlorophyll of plants?

The electronic configuration of a metal $M$ is $1s^2, 2s^2 2p^6, 3s^1$. The formula of its oxide will be