Question

Which of the following is the correct order of ionisation enthalpy ?
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 1

Correct Answer - A
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`.