Rank the effective nuclear charge Z* experienced by a valence electron in each of these atoms z experienced by a atom valence electron. An atom of phosphorus. (pick one An atom of aluminum. phosphorus, aluminum, silicon, chlorine

These atoms Aluminium, silicon , phosphorus and chlorine all belong to third period of periodic table.

Effective nuclear charge=nuclear charge- shielding constant

We know that as we move across the period electron enter same shell due to which nuclear charge (Z) increase but there is no appreciable change in shielding constant hence effective nuclear charge increase across period.

So order of effective nuclear charge among given elements is

AL<Si<P<Cl