A crystalline salt when heated becomes anhydrous and losses $51.2\%$of its weight. The anhydrous salt on analysis gave the percentage composition as $\mathrm{Mg}=20.0\%$, $\mathrm{S}=26.66\%$ and $\mathrm{O}=53.33\%$. Write the molecular formula of the salt.

Arrange the following in the increasing order of number of atoms.

I. $1 \mathrm{g}$ $\mathrm{Au}$ (s)                      II. $1 \mathrm{g}$ $\mathrm{Na}$ (s)

III. $1 \mathrm{g}$ $\mathrm{Li}$ (s)                     IV. $1 \mathrm{g}$ of ${\mathrm{Cl}}_2$ (g)

Match the following columns.

Arrange the following as per the instructions given in the bracket.

$\mathrm{Li}, \mathrm{Na}, \mathrm{K}, \mathrm{Rb}$ (increasing order of number of electron shells).

Arrange the following as per the instructions given in the bracket.

$\mathrm{Be}, \mathrm{Mg}, \mathrm{Ca}, \mathrm{Sr}$ (increasing order of atomic size).

Arrange the following as per the instructions given in the bracket.

$\mathrm{B}, \mathrm{Al}, \mathrm{Ga}, \mathrm{In}$ (increasing order of ionisation energy).

Arrange the following as per the instructions given in the bracket.

$\mathrm{C}, \mathrm{Si}, \mathrm{Ge}, \mathrm{Sn}$ (increasing order of electronegativity).

State the type of bonding present in the magnesium chloride.

State the type of bonding present in the sodium chloride.