Slater's rules

Slater's Rules are a set of rules devised by  John C. Slater that give an approximate estimate of effective nuclear charge on an electron (Z*).

$$Z*=Z-S$$

where S is the screening constant.

The system involves the two following steps:

1.Arrange sets according to principle quantum number, ignoring filling order and keeping ns and np together i.e [1s] [2s,2p] [3s,3p] [3d] [4s,4p] [4d] [4f]

2.Using the table, calculate the contributions to S (the screening constant) for electrons in each set.