Question

Question 2.63 The bromine atom possesses 35 electrons. It contains 6 electrons in 2p orbital, 6 electrons in 3p orbital and 5 electrons in 4p orbital. Which of these electron experiences the lowest effective nuclear charge?

Class XI Structure of Atom Page 69

Answer 1

4p orbitals are farthest from the nucleus of bromine atom. Thus, the electrons in the 4p orbital will experience the lowest effective nuclear charge.
Also because these 4p electrons are shielded by the electrons present in the 2p and 3p orbitals, they have the lowest effective nuclear charge.

Answer 2

Answer: 4p orbital experiences lowest effective nuclear charge.

Explanation:

Effective nuclear charge is defined as the attraction of the protons present in the nucleus of an atom to the outermost electrons.

As we move across the period, successive electrons are added to the orbitals in the same shell and the shielding of the nuclear charge by the core electrons do not change to a large amount to decrease the attraction of electron to the nucleus. Thus, effective nuclear charge is dominant than screening effect.

As, we move down the group, outermost electron gets further away from the nucleus. So, the shielding effect increases by the core electrons. Thus, the screening effect is dominant than nuclear charge in case of group. As, the principal quantum number increases, effective nuclear charge decreases and screening effect increases.

We are given a bromine atom: This atom has 6 electron sin '2p' orbital, 6 electrons in '3p' orbital and 5 electrons in '4p' orbital.

So, the principal quantum number of '4p' orbital is the highest of all the orbitals.

Thus, 4p orbital will experience lowest effective nuclear charge.