The bromine atom possesses 35 electrons. It contains 6 electrons in 2p orbital, 6 electrons in 3p orbital and 5 electron in 4p orbital. Which of these electron experiences the lowest effective nuclear charge?

Nuclear charge experienced by an electron in a multi-electron atom is dependent upon the distance between the nucleus and the orbital.
As the distance increases the effective nuclear charge decreases.
Among p-orbitals, 4p orbitals are farthest from the nucleus of bromine atoms with (+35) charge.
Therefore , the electrons in the 4p orbital will experience the lowest effective nuclear charge. These electrons are shielded by electrons present in the 2p and 3p orbitals along with the s-orbitals.

Final Answer: Hence the electrons in the 4p orbital will experience the lowest effective nuclear charge.