Question 1

What is the Balmer series and how does it relate to hydrogen emission?

Accepted Answer

The Balmer series represents spectral emission lines produced when electrons in hydrogen relax to energy level 2 from higher levels. Using the Rydberg formula with nfinal set to 2, you can calculate the distinct wavelengths of light emitted in the UV and visible range. These transitions from levels 3, 4, 5, 6, and 7 create characteristic peaks that match measured spectrophotometer data.

Question 2

How do you calculate wavelengths using the Rydberg formula?

Accepted Answer

The Rydberg formula calculates 1/λ using the Rydberg constant (1.098 × 10⁷ m⁻¹), the initial energy level (ninitial), and final energy level (nfinal). For the Balmer series, set nfinal to 2. Solve for 1/λ, then take the reciprocal and convert to nanometers. This method produces calculated wavelengths that match measured values from spectrophotometer acquisition.

Question 3

What does the spacing of peaks in a hydrogen emission spectrum reveal?

Accepted Answer

Peak spacing in the hydrogen emission spectrum reflects the energy gap between electron transitions. As electrons relax from higher energy levels to level 2, the energy gap increases by progressively smaller amounts. This creates closer peak spacing at higher wavelengths and wider spacing at lower wavelengths, a trend also observed in helium and neon spectra.

Question 4

How do you convert wavelength to frequency and energy?

Accepted Answer

Frequency in THz is calculated using the speed of light (c = 2.998 × 10⁸ m/s) divided by wavelength. Energy in eV is determined using Planck's constant (h = 6.626 × 10⁻³⁴ J·s) multiplied by frequency. These calculations reveal the energy associated with each electron relaxation transition in the Balmer series.

Question 5

Why is it harder to identify spectral series in helium and neon compared to hydrogen?

Accepted Answer

Helium and neon have more electrons than hydrogen, making their spectral series more complex. Adding even one electron to helium makes the series harder to calculate and identify. Neon, with eight more electrons than helium, shows even greater complexity because electron-electron interactions and orbital configurations complicate energy level transitions and spectral patterns.

Question 6

What are the key steps for measuring emission spectra with a spectrophotometer?

Accepted Answer

Configure the spectrophotometer to measure emission intensity with 200 ms sampling time and no sample averaging. Hold the sensor at the center of the lamp and start acquisition when the lamp turns on. Capture the spectrum quickly with minimal noise, as lamps cannot run longer than 30 seconds continuously. Save and export data for each element studied.

Question 7

What data should you record before starting the emission spectroscopy experiment?

Accepted Answer

Create a table in your lab notebook listing the elements analyzed (hydrogen, helium, neon), the observed color of light from each lamp, and the recorded wavelengths in nanometers. This organized data collection allows you to compare measured wavelengths with calculated values from the Rydberg formula and track spectral characteristics across different elements.

Elements	Color	אורכי גל מובחנים, λ (nm)
H
he
Ne

קבוע רידברג (^m-1)	1.098 × 10⁷
C (מטר לשנייה)	2.998 × 10⁸
h (J·s)	6.626 × ^10-34
ni → nf	λ_מחושב(nm)	λ_נמדד (nm)	v (THz)	E (eV)
7 → 2
6 → 2
5 → 2
4 → 2
3 → 2

סדרת Balmer

טבלה 1: אורכי גל פליטה

טבלה 2: תדר ואנרגיה לכל אורך גל

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