Chapter 18, Problem 1P

(a) What is the collective name for the group 18 elements? (b) Write down, in order, the names and symbols of these elements; check your answer by reference to the first page of this chapter. (c) What common feature does the ground state electronic configuration of each element possess?

Interpretation Introduction

Interpretation:

The collective name of the group 18 elements must be interpreted.

Concept introduction: All known elements are arranged in the form of the periodic table. Here, the elements are arranged in the increasing order of their atomic number.

The table is divided into 18 groups and 7 rows which are called periods. The elements of the same group show a periodic trend in their chemical and physical properties.

Answer to Problem 1P

The collective name of the group-18 elements is noble gases or inert elements.

Explanation of Solution

The elements of group-18 have the general electronic configuration as ${\text{ns}}^{\text{2}}{\text{np}}^{\text{6}}$ . Due to the complete octet configuration in their valence shell, these elements are least reactive or inactive with other elements or compounds. Therefore, they are also called inert elements. Since all elements exist in the gaseous state and are inactive, so they are also termed as Noble gases.

Interpretation Introduction

Interpretation:

The name and symbols of the elements of the group 18 elements must be interpreted.

Concept introduction: All known elements are arranged in the form of the periodic table. Here the elements are arranged in the increasing order of their atomic number.

The table is divided into 18 groups and 7 rows which are called periods. The elements of the same group show a periodic trend in their chemical and physical properties.

Answer to Problem 1P

Element	Name of the element
$\text{He}$	Helium
$\text{Ne}$	Neon
$\text{Ar}$	Argon
$\text{Kr}$	Krypton
$\text{Xe}$	Xenon
$\text{Rn}$	Radon

Explanation of Solution

The elements of group-18 have the general electronic configuration as ${\text{ns}}^{\text{2}}{\text{np}}^{\text{6}}$. They are also called inert elements. The name and chemical symbol for these elements are as listed below:

Element	Name of the element
$\text{He}$	Helium
$\text{Ne}$	Neon
$\text{Ar}$	Argon
$\text{Kr}$	Krypton
$\text{Xe}$	Xenon
$\text{Rn}$	Radon

Interpretation Introduction

Interpretation:

The common feature of the ground state electronic configuration of each element of the group 18 elements must be interpreted.

Concept introduction: All known elements are arranged in the form of the periodic table. Here, the elements are arranged in the increasing order of their atomic number.

The table is divided into 18 groups and 7 rows which are called periods. The elements of the same group show a periodic trend in their chemical and physical properties.

Answer to Problem 1P

The common feature for these elements is the octet configuration of all elements in their valence shell excluding Helium that has duplet configuration.

Explanation of Solution

The elements of group-18 have the general electronic configuration as ${\text{ns}}^{\text{2}}{\text{np}}^{\text{6}}$. The valence shell electronic configuration of elements is as given below:

Element	Name of the element	Valence Electronic configuration
$\text{He}$	Helium	${\text{1s}}^{\text{2}}$
$\text{Ne}$	Neon	${\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}$
$\text{Ar}$	Argon	${\text{3s}}^{\text{2}}{\text{3p}}^{\text{6}}$
$\text{Kr}$	Krypton	${\text{4s}}^{\text{2}}{\text{4p}}^{\text{6}}$
$\text{Xe}$	Xenon	${\text{5s}}^{\text{2}}{\text{5p}}^{\text{6}}$
$\text{Rn}$	Radon	${\text{6s}}^{\text{2}}{\text{6p}}^{\text{6}}$

The common feature for these elements is the octet configuration of all elements in their valence shell excluding Helium, which has a duplet configuration.

This configuration makes them stable and least reactive compare to other elements.