Many-electron Atoms

Abstract

We have seen in the last chapter that the energy of an electron in a one-electron atom or ion is given by Equation 3.49 as:

$$\mathop E\nolimits_n = - \mathop Z\nolimits^2 {R \over {\mathop n\nolimits^2 }}.$$

For a given integer n, the energy decreases as the square of the atomic number (or charge on the nucleus) increases, and for given atomic number there is an array of energy levels available similar in number to that for hydrogen given in Figure 3.6, but with a different energy scale for each different value of the atomic number. The other important feature in the description of one-electron systems is that when Z increases, the size of the orbital decreases, the decrease being approximately inversely proportional to the nuclear charge.