effective nuclear charge and its calculation

The effective nuclear charge on the added electron in F-atom , in the formation of negative ion is

The effective nuclear charge for an electrone for the outermost electron in (14)/(7)N is

Describe how effective nuclear charge changes along a period and a group in a periodic table.

Calculate the effective nuclear charge of the last electron in an atom. The electronic configuration is 1s^(2), 2s^(2)2p^(6), 3s^(2)3p^(5) .

Statement: The acidic nature of some cations is: B^(3+)gtBe^(2+)gtNa^(+)gtK^(+) Explanation: More is the effective nuclear charge on cation more is its acidic nature.