What is the oxidation state of iodine in $\mathrm{I}_2 \mathrm{Cl}_6$ ?

Chlorine exists in two isotopic forms ${ }^{35} \mathrm{Cl},{ }^{37} \mathrm{Cl}$. If average atomic mass of chlorine is 35.5 , what is the percentage abundance of these isotopes respectively?

Which element from following has completely filled f-orbital in observed and expected electronic configuration?

Which from following monomers is used to obtain polymer represented as