Bohr's explanation of the Balmer Series

#### Introduction

- Recall from before that the wavelengths of Balmer series can be found by:

\begin{align} \frac{1}{\lambda} = R_h [Z^2] \bigg(\frac{1}{{n_f}^2} - \frac{1}{{n_i}^2}\bigg) \end{align}

- Bohr explained this mathematical equation in terms of his model of the atom:
- Bohr thought that the equations described the wavelengths of the
**photons emitted**when making the**transition**from excited states to lower states. - He thought that $n_i$ described the
**higher**state of the electron and $n_f$ described the**lower**state that it travelled to.

- Bohr thought that the equations described the wavelengths of the
- This was reinforced by the Infra-red spectrum of the
**Paschen series,**which supported the equation. (**n = 3**) - Later, more series' were found, these include:
- The
**Lyman Series,**which were**Ultraviolet**lines to the**Ground state**(n = 1) found in 1916 - The
**Brackett series,**which were**Infra-red**lines to the 3rd excited state (**n = 4**) found in 1922 - The
**Pfund series,**which were**Infra-red**lines to the 4th excited state (**n = 5**) found in 1924

- The

#### Diagrammatical information.

**Important!**

- You will need to be able to draw the circle on the right. Knowing the left side doesn't hurt.
- While the diagram shows other wise, you must realise that
**the lines get closer**as n gets larger.

page revision: 1, last edited: 11 Jul 2011 11:21