Effective Charge of an Atom

[Sarina Morales 1D]

Why is the effective nuclear charge dependent on the number of electrons present in an atom? Is there a specific equation I should look at to support this?

[Alejandra Reyna 1E]

The effective nuclear charge is dependent on the number of electrons present in an atom because the nuclear charge increases from bottom to top and right to left. For example, Lithium (row 2) would have a higher nuclear charge than Potassium (row 4). Another example would be Carbon (column 14) having a higher nuclear charge than Phosphorous (column 15). Hope this helps!

[Wu Yuchen A1]

I guess you are talking about shielding effect? When multiple electrons move around nucleus, different shell experience different effective nucleus charge because inner shell shields out shell.