Chapter 5, Problem 19P

Interpretation Introduction

Interpretation: Electronic configuration of ${\text{Be}}^{+}$ , ${\text{C}}^{-}$ , ${\text{Ne}}^{+2}$ , ${\text{Mg}}^{+}$ , ${\text{P}}^{-2}$ , ${\text{Cl}}^{-}$ , ${\text{As}}^{+}$ and ${\text{I}}^{-}$ in ground state and whether they are paramagnetic or not should be reported.

Concept introduction: Electronic configuration of elements in ground state is assigned to elements only when they follow certain rules like Hund’s rule, Pauli Exclusion Principle and Aufbau rule. If $Z$ is the atomic number then the $Z$ number of electrons are filled into the orbitals arranged in the order of increasing energy. This is Aufbau rule.

No two electrons in an atom can have same group of four quantum numbers and this is Pauli Exclusion Principle.

While orbitals are filled, one electron first enters to each energy level with degenerate energy before paring begins and this is Hund’s rule.