Order of increasing Ionization Energy is Kr>As>Sb >Sn.
Explanation:
In the periodic table, the ionization energy increases when we move across the period also decreases when we move down the group. Tin (Sn) is in the carbon group, Arsenic and antimony is present in nitrogen group(Sb,As), and Krypton is present in Helium group(Kr). As we know, Helium or zero group elements have maximum ionization energy, since it has fulfilled orbitals, So Kr has the maximum ionization energy, where as As and Sb is present in lower periods than that of Krypton and then comes tin.
So ionization energy is in the increasing order of Kr>As>Sb >Sn.
Hence the order follows as,Kryton>Arsenic>Antimony>Tin
