Among following species which of them have maximum `Z_(eff)`

Choose the following atom which has maximum value of Z_("eff") ?

Which one of the following species will have maximum bond dissociation energy?

Which of the following species have maximum number of electrons ?

Which of the following species have maximum number of electrons ?

Which of the following species have maximum number of unpaired electrons ?

Which among the following species is an elastomer?

Which among the following species is an elastomer?

Among the following pairs, in which one from first species to second species decrease in radius is maximum