Lecture on Hydrogen Emission Spectrum
Understanding Light
- White Light and Prisms
- When white light passes through a prism, it refracts into a continuous spectrum of colors (rainbow).
- Visible spectrum is the part of light we can see.
- Continuous Spectrum
- Shows all frequencies of light in the visible range.
Hydrogen Emission Spectrum
- Experiment with Hydrogen Gas Lamp
- Unlike white light, a hydrogen gas lamp emits a line spectrum.
- Line spectrum: only specific frequencies of light are emitted.
- Important to refer to frequencies, not colors, for exams.
- Hydrogen Emission Spectrum
- Produced when hydrogen gas is excited by energy.
Atomic Structure and Energy Levels
- Hydrogen Atom Model
- Nucleus at the center with electron in the lowest energy level (ground state).
- Electron Excitation
- Electrons absorb specific frequencies of energy to jump to higher energy levels.
- Must absorb exact energy difference between levels.
- Electron Emission
- Release the same amount of energy as absorbed when returning to lower energy levels.
Bohr Model and Energy Levels
- Energy Level Diagram
- Simplified diagram showing energy levels, labeled as n=1, n=2, etc.
- Hydrogen Emission Spectrum Analysis
- Red line: Transition from n=3 to n=2 (lowest energy/frequency drop).
- Green line: Transition from n=4 to n=2.
- Blue line: Transition from n=5 to n=2.
- Violet line: Transition from n=6 to n=2.
- Convergence of Energy Levels
- Higher energy levels converge as they move outward.
- Lines in emission spectrum also converge.
Implications and Observations
- Visible Spectrum
- Emissions to n=2 level correspond to visible light.
- Other Spectra
- Drops to n=1 (first level) observed in UV spectrum (high energy).
- Drops to n=3 seen in infrared spectrum (low energy).
- Expectations of convergence in these spectra as well.
Summary of Key Points
- Emission Spectra
- Produced by excited electrons releasing energy as they drop to lower levels.
- Hydrogen Emission Insight
- Electron energy levels are discrete and converge at higher energies.
- Visible Spectrum Lines
- Result from drops to the n=2 energy level.
- Drops to n=1 in UV, to n=3 in infrared spectra.
This lecture provides insights into how the hydrogen emission spectrum is related to atomic structure and energy levels, significantly illustrating the concept of discrete energy levels in atoms.