Structure 1.3.2—The line emission spectrum of hydrogen provides evidence for the existence of

electrons in discrete energy levels, which converge at higher energies

**What You’ll Learn:**

- Describe the emission spectrum of the hydrogen atom, including the relationships between the lines and energy transitions to the first, second and third energy levels.
- The names of the different series in the hydrogen emission spectrum will not be assessed.

**Keywords**

Emission spectra, excited states, lower energy levels, electromagnetic spectrum, wavelength, frequency, energy, continuous spectrum, line spectrum, hydrogen emission spectrum, energy transitions, Balmer series, Lyman series, Paschen series, Rydberg formula, principal quantum number (n), maximum number of electrons, Aufbau principle, main energy level, sublevels (s, p, d, and f), atomic orbitals, s orbital, p orbitals (p_{x}, p_{y}, and p_{z}),

d orbitals (d_{xy}, d_{xz}, d_{yz}, d_{x²-y²}, and d_{z²}), orbital shapes and orientations, nodal planes, electron configuration, chemical environment, opposite spin, Aufbau principle, Hund’s rule, Pauli exclusion principle, full electron configurations, condensed electron configurations, noble gas core, orbital diagrams (arrow-in-box diagrams)

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**Syllabus Links**

Inquiry 2—In the study of emission spectra from gaseous elements and of light, what qualitative and quantitative data can be collected from instruments such as gas discharge tubes and prisms?

Nature of science, Structure 1.2—How do emission spectra provide evidence for the existence of different elements?

The line emission spectrum of hydrogen provides evidence for the existence of electrons in discrete energy levels, which converge at higher energies. This can be described through the following points:

- Hydrogen emission spectrum: The hydrogen emission spectrum consists of a series of discrete lines that correspond to specific energy transitions within the hydrogen atom. When a hydrogen atom is excited, its electron moves to a higher energy level. As the electron returns to lower energy levels, it emits photons with energies specific to the energy level transitions. These emitted photons correspond to specific wavelengths, which appear as distinct colored lines in the spectrum.
- Energy transitions and series: The emission spectrum of hydrogen can be categorized into several series based on the energy levels involved in the transitions. Each series corresponds to a different set of transitions, where the electron returns to a particular energy level (n). The series are named after the scientists who discovered them:
- Lyman series: Transitions where the electron returns to the first energy level (n=1). These lines are in the ultraviolet region of the spectrum.
- Balmer series: Transitions where the electron returns to the second energy level (n=2). These lines are in the visible region of the spectrum.
- Paschen series: Transitions where the electron returns to the third energy level (n=3). These lines are in the infrared region of the spectrum.

As the energy levels increase, the energy differences between adjacent levels decrease, causing the spectral lines in the series to converge at higher energies.

- Calculating spectral lines: The wavelengths of the spectral lines in the hydrogen emission spectrum can be calculated using the Rydberg formula:1/λ = R
_{H}(1/n1² – 1/n2²)where λ is the wavelength of the emitted photon, R_{H}is the Rydberg constant for hydrogen (approximately 1.097 x 10^{7}m^{-1}), n1 is the lower energy level (the level the electron returns to), and n2 is the higher energy level (the level the electron was initially excited to).

To calculate the wavelengths of the spectral lines, you can plug in the appropriate values for n1 and n2 based on the series you are considering (e.g., n1=1 for Lyman series, n1=2 for Balmer series, and n1=3 for Paschen series) and solve for λ.

In conclusion, the line emission spectrum of hydrogen provides evidence for the existence of electrons in discrete energy levels, as demonstrated by the distinct series of lines corresponding to specific energy transitions. The relationships between the lines and energy transitions to the first, second, and third energy levels can be understood through the Lyman, Balmer, and Paschen series, respectively. The Rydberg formula can be used to calculate the wavelengths of the spectral lines for each series.

Questions

- What is the hydrogen emission spectrum and what does it consist of?
- How does the movement of an electron in a hydrogen atom relate to the emission of photons?
- What are energy transitions in the hydrogen atom and how are they related to the emission spectrum?
- What are the different series of lines in the hydrogen emission spectrum and what energy levels are involved in each series?
- How do the spectral lines in the hydrogen emission spectrum converge at higher energies?
- What is the Rydberg formula and how is it used to calculate the wavelengths of spectral lines in the hydrogen emission spectrum?
- What is the significance of the Lyman series in the hydrogen emission spectrum?
- What is the significance of the Balmer series in the hydrogen emission spectrum?
- What is the significance of the Paschen series in the hydrogen emission spectrum?
- How does the line emission spectrum of hydrogen provide evidence for the existence of electrons in discrete energy levels?