On which equation are the reactants located

If it is an isoelectronic series select true, if not select false. o2-, s2-, se2-, te2- na+, k+, rb+, cs+ n3-, p3-, as3-, sb3- ag, cd+, sn3+, sb4+ f-, cl-, br-, i- f-, ne, na+, mg2+ s2-, s, s6+

Which is an example of a highly unstable isotope that is often used in fission reactions?

What is dhmo? hint: you find it everywhere something is wet..