# Can anyone give me a model answer for this question??? (1 Viewer)

#### Petyo

##### Member
The question is:
Analyse the significance of the hydrogen spectrum in the development of Bohr's model of the atom.( 5 Marks)

#### alcalder

Well, you're going to need to talk about:
1. The specific wavelengths of the lines in the hydrogen spectrum and where they lie (red blue green and Hmmm, forgot where).
2. How coloured light corresponds to a particular energy given by the equation with Energy and wavelength.
3. That excited atoms give off light because electrons have absorbed and then reemit the energy at specific wavelengths.
4. That these specific wavelengths then correspond to the drop from one energy level to another and
5. That there was a correlation given by Bohr's equation that could predict the wavelengths of these lines.

Something like that.

#### darkchild69

##### Nanotechnologist
The spectral lines of hydrogen are produced when hydrogen gas is excited using a high-voltage source. This means that the electrons in the atom are actually excited, and thus emit radiation. Importantly, the visible spectrum of the hydrogen atom, called the Balmer series of spectral lines, corresponds to a series of bands, meaning that only certain wavelength of light are actually being emitted by the atoms. This fitted with what Planck said about the energy being radiation being quantised.

Balmer was able to derive an empirical equation for the wavelengths of the spectral lines of hydrogen, which was later modified by Rydberg:

<<Insert eqn here>>

Where RH is the Rydberg constant, given on the data sheet
And ni and nf are integers.

Balmer of course did not know what these integers represented, they simply fitted the data well.

Bohr’s challenge was to then try to explain these spectral lines, and he set out to do this by assuming that the energy was quantised, and that the orbits of the electron were circular. This explanation is described in his postulates.

This empirical equation for the wavelengths of the hydrogen spectrum therefore led to the development of Bohr’s postulates, from which a theoretical equation may be derived that supports Balmer’s empirical equation.