ABSTRACT
The classical picture of the electron is of a tiny particle whose position in space can be accurately defined by its co-ordinates x,y and z. Its motion in an atom is then described by the variation of (x,y,z) with time. This was the way in which Rutherford and Bohr described the atom on a 'planetary' model with the massive central nucleus and the light electrons moving in 'orbits' around it. However, it was shown in the 1920s that moving particles should behave in some ways as waves and that this effect should be particularly marked for a particle as light as the electron. Experimental support for this prediction was soon found. It was shown, for example, that a beam of electrons could be diffracted by a suitable grating in exactly the same way as a beam of light. These wave properties were introduced into the theory of atomic structure by Schrôdinger in his wave mechanics in which the electron in an atom is described by a wave equation.
