Which of the following electronic configurations in the outermost shell is characteristic of alkali metals?

Which of the following alloys are correctly matched with their uses?
$(i)$ $Li-Mg$ armour plates
$(ii)$ $Cu-Be$ high strength springs
$(iii)$ $Mg-Al$ aircraft construction

The correct order of electrical conductivity of alkali metal ions in their aqueous solution for $Cs^{+}$, $K^{+}$, $Na^{+}$, and $Li^{+}$ is:

Given below are two statements,one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: The alkali metals and their salts impart characteristic colour to reducing flame.
Reason $R$: Alkali metals can be detected using flame tests.
In the light of the above statements,choose the most appropriate answer from the options given below.

The correct order of solubility for the given compounds is:

Which of the following is the chemical formula for dolomite?