Which of the following process requires the largest amount of energy ?

Options

A. `K^(+) to K^(2+) + e^(-)`
B. `Li^(+) to Li^(2+) + e^(-)`
C. `Fe to Fe^(+) + e^(-) `
D. `Ca^(+) to Ca^(2+) + e^(-)`

Answer

B

Explanation

`IE_2` of alkali metal is high. Out of all alkali metal, `IE_2` is highest for `Li^(+)` due to its very small size.