Which of the following is wrong ?

Options

A. `NH_(3) lt PH_(3) lt AsH_(3)` (acidic character)
B. `Li lt Be lt B lt C(IE_(1))`
C. `A1_(2)O_(3) lt MgO lt Na_(2)O lt K_(2)O` (basic)
D. `Li^(+) lt Na^(+) lt K^(+) lt Cs^(+)` (inoic radius)

Answer

B

Explanation

`B` has unusually low `IE_(1)` than `Be` because in `B`. The ionized electron is a `p` electron from the `2nd` shell while in `Be`, the ionized electron is an `s` electron from the `2nd` shell. For a given value of `n`, the case of removal of electron is
`sgt p gt dgt f`
The correct order is
`Li (520 kJ mol^(-1)) lt B (801) lt Be (899) lt C (1086)`