Which of the following is the correct order of ionisation enthalpy ?

Options

A. `Te^(2-) lt I lt C lt Ba^(2+)`
B. `I^(-) lt Te^(2-) lt Cs lt Ba^(2+)`
C. `Ts^(2-) lt Cs lt I^(-) lt Ba^(2+)`
D. `Ba^(2+) lt Cs^(+) lt I^(-) lt Te^(2-)`

Answer

A

Explanation

All are isoelectronic species but as number of protons i.e atomic number increases, the attraction between electron (to be removal) and nucleus increases and thus ionisation enthalpies increase.
Order of `Z: Te^(2-) (52) lt I^(-) (53) lt Cs^(+) (55) lt Ba^(2+) (56)`. So same will be the order of `IE`.