Consider one `He^+` ion in excited state `(n = 5)`. Which of the following of the following observations will hold true as per the Bohr's model.

Options

A. `10` emission spectral lines will be seen.
B. The ionization energy needed is less than `2 eV`.
C. The longest emitted wavelength is less than `10//R` (`R =` Rydberg's constant).
D. The electronic separtion from the centre of nucleus is more than `6 Å`.

Answer

D

Explanation

A sample of `He^(+)` will produce `10` possible emission spectral line. A single `He^(+)` can produce maximum `4` lines (not more)
`5rarr4rarr3rarr2rarrr1`
`E_(n) = -13.6 xx (2^(2))/(5^(2)) = 2.17 eV`
`(1)/(lambda) = RZ^(2)((1)/(n_(1)^(2)) - (1)/(n_(2)^(2)))`
`(1)/(lambda) = R.4((1)/(4^(2)) - (1)/(5^(2)))`
or `lambda = (100)/(9R) gt (10)/(R)`
`r_(n) = 0.529 xx (5^(2))/(2)A gt 6Å`