Chapter 3.7, Problem 5QQ

Interpretation Introduction

Interpretation:

The number of different orbitals that contain electrons for the atom that has electronic configuration as $1s^{2}2s^{2}2p^2$ has to be chosen from the given options.

Concept Introduction:

Electronic configuration of an atom describes how many electrons are present in the shell.  Many orbitals are present about the nucleus of an atom.  In these orbitals the electrons do not occupy randomly.  There are three rules for assigning the electrons to various shells, subshells, and orbitals.  They are,

• The subshells are filled in increasing order of energy.
• In a subshell, the electrons occupy the orbital singly first in all orbitals before pairing up by the second electron.  All the electrons that are in singly occupied orbitals have same spin.
• In a given orbital there cannot be more than two electrons and they have opposite spins.

Electronic configuration of an element is the one that gives information about how many electrons are present in each electron subshell of an atom.  The electrons are added to the subshells in increasing order of energy.  Electronic configurations are written in shorthand notation which uses a number‑letter combination.  The shell is indicated by the number and subshell is indicated by the letter.  Superscript that follows the subshell tells how many electrons are present in the subshell.

The order of filling up the electrons in the subshell is done as shown in the given figure below.

Orbital diagram is the one that gives information about the number of electrons present in the electron orbitals of an atom.  The difference between electronic configuration and orbital diagram is that electronic configuration deals with the electrons occupancy in the subshell while orbital diagram deals with the electrons occupancy in the electron orbital.  Electrons are paired up in the orbital only when all the orbitals in the subshell are singly filled.