O1
O2
CO1: spectra, spectral lines
CO2: Bohr model, Bohr's postulates
Require of students with no. 1 to determine the wavelength’s values of spectral lines of hydrogen in comparison with the known spectral lines of mercury.
Request of students with no. 2 to calculate the differences Ek – E2 (in eV).
Presentation of tasks
O3
O4
Leading learning
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CO3: Bohr model, Bohr's postulates
CO4: Bohr model, Bohr's postulates
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Require of students with no. 3 to calculate the energies of photons emitted by the electron’s transitions from higher levels of n on it.
Require of students no. 4 to calculate the wavelengths of photons with energies: hν32 = E3 E2; hν42 = E4 - E2; hν52 = E5 - E2; hν62 = E6 - E2. Require of students to achieve individual activities, then to consult with the team, to draw conclusions in agreement, to record the final results, behind the conclusions.
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Students from first group determine the wavelength’s values of the spectral lines of hydrogen (observed). Students from second group show that the emitted photons (whose wavelengths are given in advance by the teacher on the worksheet) should have the energies: 1,89 eV; 2,55 eV; 2,86 eV; 3,03 eV Students from third group show the possible values for energies of photons emitted from the transitions on higher level to n = 2, (mathematically calculated as Bohr's model): 1,89 eV; 2,55 eV; 2,86 eV; 3,03 eV. Students from fourth group show the values of wavelengths of photons having energies given by worksheet. Perform individual tasks distributed, they consult on the results obtained, reach a consensus, record the results agreed.
Evaluation of the accuracy of wavelength’s values obtained by students.
Evaluation of how to obtain energy values recorded for differences required.
Evaluation of the accuracy of values for energies of photons emitted from the transitions on higher level to n = 2, calculated by the students. Evaluation of the accuracy of wavelength’s values obtained by students.
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