Which of the following ions have pseudo Noble gas configuration :Ag+, K+, Mg2+, Zn2+, S2-, Sn2+, Ga3+, O2-, N3-, cl-

Total number of structural isomers of 
[Co(NH₃)₆][Cr(CN)₆]

Why is boiling point of Cesium higher than that of Rubidium

 

which isomer mentioned in (a) is water soluble and why?

A gaseous mixture contains CO2 and CO the mass of the mixture is 200g and they are presenting equal fraction of moles . Find the total no. of O-atoms present in the mixture.