The energy of the electron in the first orbit of `He^+` is `- 871.6 xx 10^-20 J`. The energy of the electron in the first orbit of hydrogen would be.

Options

A. `-871.6 xx 10^(-20) J`
B. `-435.8 xx 10^(-20) J`
C. `-217.9 xx 10^(-29) J`
D. `-108.9 xx 10^(-20) J`

Answer

C

Explanation

`E_(1_(He^(+))) = E_(1H) xx Z^(2)`
`therefore - -871.6 xx 10^(-20) = E_(1H) xx 4`
`therefore E_(1H) = - 217.9 xx 10^(-20)J`