Solution
Related Formula
ν = RH Z² [(1)/(n₁²) - (1)/(n₂²)]Core Logic
For the Balmer series in a Hydrogen atom (Z=1), the lower energy level is always n₁ = 2. The higher energy levels are n₂ = 3, 4, 5,
Step 1: Calculate First 3 Lines of Balmer Series
If n₂ = 3 (First line):\nν = R(1)² [(1)/(2²) - (1)/(3²)] = R [(1)/(4) - (1)/(9)] = (5R)/(36)\n\nIf n₂ = 4 (Second line):\nν = R [(1)/(4) - (1)/(16)] = R [(3)/(16)] = (3R)/(16)\n\nIf n₂ = 5 (Third line):\nν = R [(1)/(4) - (1)/(25)] = R [(21)/(100)] = (21R)/(100)
Final Conclusion
The set (5R)/(36), (3R)/(16), (21R)/(100) correctly matches the first three spectral lines of the Balmer series.
Pattern Recognition
Rydberg fractions for Balmer start exclusively with denominators involving common multiples of 4 and squares: 4 × 9 = 36, 4 × 16 = 64 arrow 16, 4 × 25 = 100.
Chapter Mix
Class 11 Chemistry: Structure of Atom