BITSAT2019ChemistryStructure of AtomActual
The wavelength corresponding to maximum energy for hydrogen is 91 . 2 nm . The corresponding wavelength for He + ion is
Options
- A2 . 28   nm
- B22 . 8   nm
- C182 . 4   nm
- D364 . 8   nm
Correct answer
B. 22 . 8   nm
Step-by-step solution
Accordinq to Rydberg's equation v ¯ = 1 λ = RZ 2 1 n L 2 - 1 n H 2 where, v ¯ = wave number λ = wavelength R = Rydberg constant = 109677   cm - 1 Z = atomic number n L = lower energy state n H = higher energy state. i.e. 1 λ ∝ Z 2 Thus, λ He + λ H = Z 2 H Z 2 He + To find λ He + = ? Given, λ H = 91 . 2   nm Z H = 1 Z He = 2 ∴   λ He + = 1 × 91 . 2 4 = 22 . 8   nm