Chapter 4.5, Problem 7PPB

Interpretation Introduction

Interpretation:

The list of atoms and species that matches with the given electronic configuration should be determined.

Concept Introduction:

Periodic Table: The available chemical elements are arranged considering their atomic number, the electronic configuration and their properties. The elements placed on the left of the table are metals and non-metals are placed on right side of the table.

In periodic table the horizontal rows are called periods and the vertical column are called group.

In periodic table the horizontal rows are called periods and the vertical column are called group. There are seven periods and 18 groups present in the table and some of those groups are given special name as follows,

$\begin{array}{l}\text{Group-1}\to \text{Alkali metal}\\ \text{Group-2}\to \text{Alkaline metals}\\ \text{Group-16}\to \text{Chalcogens}\\ \text{Group-17}\to \text{Halogens}\\ \text{Group-18}\to \text{Noble gases}\end{array}$

Atomic Number: Atomic number of the element is equal to the number of protons present in the nucleus of the element which is denoted by symbol Z. The superscript presents on the left side of the symbol of the element.

Atomic radius:

Atomic radius is the distance between the atomic nucleus and outermost electron of an atom. From the atomic radius, the size of atoms can be visualized. But there is no specific distance from nucleus to electron, due to electron cloud around the atom does not have well-defined boundary.

The atomic radius follows the trend that it tends to decrease as we move from left to right as the effective nuclear charge increases and the radius tends to increases from top to bottom of the group since shells gets added to the atom.

Cation: Removal of electron from the atom results to form positively charged ion called cation.

Anion: Addition of electron to atom results to form negatively charged ion called anion.

The net charge present in the element denotes the presence or absence of electrons in the element.

Effective nuclear charge: It is the overall positive charge experienced by the outermost electrons present in the atom from the nucleus of the atom.

Screening Effect: The core electrons present near the nucleus shields the outermost electrons (valence electrons) from the charge of the nucleus.

Isoelectronic species: Two species are considered to isoelectronic species if they have equal number of electrons with them.

Electronic configuration: It is used to represent the distribution of electrons placed over orbitals that present in the atom.

The rules followed by the electrons are as follows,

The electrons gets distributed strictly following the order starting from lower energy orbital to higher energy orbital(Aufbau principle), pairing of electrons in subshell starts only when all the orbitals in the subshell are singly filled (Hund’s Rule) and finally, no two electrons that have same set of quantum numbers (Pauli’s Exclusion Principle).

To determine: The atoms or ions that matches with the given configuration $1s^2,2s^2,2p^6$.