Moseley diagram

Fig. 2. Moseley diagrams for the energy of removal of an outer 2 s or 2 p electron. The straight lines give the theoretical values for large Z, the circles experimental...

Moseley diagram. (Mosely curve). A graph showing the relationship between atomic numbers of a series of elements and the wavelengths of their corresponding spectral hnes. 

A graph of the reciprocal of the square root of the wavelengths of x-ray lines, for the K line and the line, of elements, plotted against the order of the elements in the periodic table. This graph, called the Moseley diagram, was used by Moseley in determining the atomic numbers of the elements. 

Use the Moseley diagram (Figure 4-2) to make a prediction of the approximate value of the wavelength of the K x-ray emission line of argon. Can you surmise why it was not measured by Moseley ... 

Here C and a are constants characterizing a particular spectral series. Moseley s law can be derived from the simple Bohr atomic model (Sect.2.1) taking shielding into account. A Moseley diagram for Ka and La emission is shown in Fig.5.3. Using such a diagram the identification of different elements in a sample is greatly facilitated. 

Moseley s law puts at our disposal a simple method of testing the order of succession in the periodic system. If we plot points in a diagram, with abscissa 2, and with ordinate the square root of the frequency of the Z -lines, the points of the diagram, as determined by... 

In the study of the X-ray literature, the wavelengths of a number of lines were noted which appeared inconsistent with the remaining data. A Moseley-type diagram was constructed, and if the value was clearly outside estimated probable error, it was assumed that an experimental or typographical enor had occurred, and the interpolated value was listed in the table. Such cases are marked with a da r (f) as a superscript to the wavelength. For elements of atomic number 85 through 89 and 91, there are no measured lines of the A series and very few of other series except for 88 radium and 91 protactinium. Likewise there are very few measurements for 43 technetium and 54 xenon. In these cases, interpolated values are listed for the more prominent lines and marked with a dagger (t). 

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