Chapter AS, Problem 20PQ

Interpretation Introduction

Interpretation:

The species with ground state electronic arrangement $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}$ has to be identified.

Concept Introduction:

To write electronic configuration certain rules have to be followed such as Hund rule, Pauli Exclusion Principle and Aufbau rule.

If $Z$  is the atomic number then the electrons that are filled into the orbitals are $Z$. Electrons are generally filled in order of increasing energy. In an atom, 2 electrons can never have same group of 4 quantum numbers and this is Pauli Exclusion Principle.

When orbitals are degenerate then each orbital is first filled with 1 electron each before the second electron enters an orbital and this is Hund’s rules.