Which one of the following has the highest neutron to proton ratio ?

Options

A. `""_8O^16`
B. `""_2He^4`
C. `""_26Fe^56`
D. `""_92 U^235`

Answer

D

Explanation

For `""_92U^235`, no. of protons = 92
`therefore` No. of neutrons = 235 - 92 = 143
`therefore` it has the highest neutron to proton ratio of `(143/92)`
(a) For `""_8O^16` it is 1:1
(b) For `""_2He^4` it is 1:1
(c ) For `""_26Fe^56` it is `30/26`