Long Answer TypeWhat are the limitations (drawback or shortcomings) of Bohr's model of atom?
The main limitations of Bohr’s model are:
1. Bohr’s theory could successfully explain hydrogen spectrum and spectra of single electron species, but it failed to explain the spectra of multielectron atoms (atoms containing more than one electron).
2. Bohr’s theory failed to explain the splitting of spectral lines into a group of finer lines under the influence of a magnetic field (Zeeman effect) and of an electrical field (Stark effect).
3. Bohr’s theory failed to explain the motion of an electron in an atom in three dimensions.
4. Bohr’s theory could not explain the shapes of molecules formed by the combination of atoms.
5. de-Broglie (in 1923) suggested that electron has a dual character. It behaves like a particle as well as like a wave. But Bohr had treated electron only as a particle.
6. Bohr’s theory assumes that an electron revolves around the nucleus at a certain fixed distance from the nucleus with a definite velocity. This is not in accordance with Heisenberg’s uncertainty principle.
What is Rydberg formula? What is the value of Rydberg constant ? What is its significance?
Calculate the wavelength of the first and limiting spectral line in the Lymann series of hydrogen spectrum.
Calculate the wavenumber for the longest wavelength transition in the Balmer series of atomic hydrogen.
Short Answer TypeWhat transition in the hydrogen spectrum would have the same wavelength as the Balmer transition n = 4 to n = 2 of He+ spectrum?
Emission transitions in the Paschen series end at orbit n = 3 and start from orbit n and can be represented as
v = 3.29 x 1015 (Hz) [1/32- l/n2.]
Calculate the value of n if the transition is observed at 1285 nm. Find the region of the spectrum.
Long Answer TypeCalculate the wavelength for the emission transition if it starts from the orbit having radius 1.3225 nm and ends at 211.6 pm. Name the series to which this transition belongs and the region of the spectrum.
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