Chapter 2, Problem 70E

(a)

Interpretation Introduction

Interpretation:

From the atomic numbers given, the corresponding elements and their most stable ions has to be identified.

Concept introduction:

Atom is the smallest fundamental unit of matter.  Atom is made up of subatomic particles like electrons, protons and neutrons.  Protons and neutrons are present in the nucleus and called nucleons.  Electrons are present in orbitals, outside the nucleus.  During chemical transformations electrons are being exchanged between the elements.  The arrangement of electrons in various atomic or molecular orbital are called electronic configuration.  For example the atomic number of sodium is 11, which means it has 11 electrons.  The electronic configuration of neutral sodium atom is written as given below.

${}_{11}{\text{Na -1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^1$

Electronic configuration indicates the chemical properties and reactivity of the element.

Atomic number is the number of electrons or the number of protons present in that atom. It is the main characteristic of an atom on which most of the properties are dependent.  Mass number is the sum of all the protons and neutrons present in the nucleus.

Answer to Problem 70E

The element is found to be aluminium and the most stable ion of aluminium is ${\text{Al}}^{3+}$

Explanation of Solution

Atomic number given is $13$. From the periodic table we can identify that the element with atomic number $13$ is aluminium $\left({}_{13}\text{Al}\right)$.

Aluminium - $\left[\text{Ne}\right]{\text{ 3s}}^{\text{2 }}{\text{3p}}^{\text{1}}$

The valance shell electronic configuration for aluminium is given above.  From which we can see that if aluminium loses three electrons from the outer most orbital, it acquires the configuration of inert gas neon, which is a highly stable configuration.  Hence, the most stable ion of aluminium will be ${\text{Al}}^{3+}$.

(b)

Interpretation Introduction

Interpretation:

From the atomic numbers given, the corresponding elements and their most stable ions has to be identified.

Concept introduction:

Atom is the smallest fundamental unit of matter.  Atom is made up of subatomic particles like electrons, protons and neutrons.  Protons and neutrons are present in the nucleus and called nucleons.  Electrons are present in orbitals, outside the nucleus.  During chemical transformations electrons are being exchanged between the elements.  The arrangement of electrons in various atomic or molecular orbital are called electronic configuration.  For example the atomic number of sodium is 11, which means it has 11 electrons.  The electronic configuration of neutral sodium atom is written as given below.

${}_{11}{\text{Na -1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^1$

Electronic configuration indicates the chemical properties and reactivity of the element.

Atomic number is the number of electrons or the number of protons present in that atom. It is the main characteristic of an atom on which most of the properties are dependent.  Mass number is the sum of all the protons and neutrons present in the nucleus.

Answer to Problem 70E

The element is found to be selenium and the most stable ion of selenium is ${\text{Se}}^{\text{2-}}$

Explanation of Solution

Atomic number given is $34$. From the periodic table we can identify that the element with atomic number $34$ is selenium $\left({}_{\text{34}}\text{Se}\right)$.

Selenium - $\left[\text{Ar}\right]{\text{ 3d}}^{\text{10}}{\text{ 4s}}^{\text{2}}{\text{ 4p}}^{\text{4}}$

The valance shell electronic configuration for selenium is given above.  From which we can see that if selenium gains two electrons, it acquires completely filled electronic configuration.  It is easy to gain two electrons than losing six electrons.  Hence, the most stable ion of selenium will be ${\text{Se}}^{\text{2-}}$.

(c)

Interpretation Introduction

Interpretation:

From the atomic numbers given, the corresponding elements and their most stable ions has to be identified.

Concept introduction:

Atom is the smallest fundamental unit of matter.  Atom is made up of subatomic particles like electrons, protons and neutrons.  Protons and neutrons are present in the nucleus and called nucleons.  Electrons are present in orbitals, outside the nucleus.  During chemical transformations electrons are being exchanged between the elements.  The arrangement of electrons in various atomic or molecular orbital are called electronic configuration.  For example the atomic number of sodium is 11, which means it has 11 electrons.  The electronic configuration of neutral sodium atom is written as given below.

${}_{11}{\text{Na -1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^1$

Electronic configuration indicates the chemical properties and reactivity of the element.

Atomic number is the number of electrons or the number of protons present in that atom. It is the main characteristic of an atom on which most of the properties are dependent.  Mass number is the sum of all the protons and neutrons present in the nucleus.

Answer to Problem 70E

The element is found to be barium and the most stable ion of barium is ${\text{Ba}}^{\text{2+}}$

Explanation of Solution

Atomic number given is $56$. From the periodic table we can identify that the element with atomic number $56$ is barium $\left({}_{\text{56}}\text{Ba}\right)$.

Barium - $\left[\text{Xe}\right]{\text{ 6s}}^{\text{2}}$

The valance shell electronic configuration for barium is given above.  From which we can see that if barium gains loses electrons, it acquires completely filled electronic configuration.  Hence, the most stable ion of selenium will be ${\text{Ba}}^{\text{2+}}$.

(d)

Interpretation Introduction

Interpretation:

From the atomic numbers given, the corresponding elements and their most stable ions has to be identified.

Concept introduction:

Atom is the smallest fundamental unit of matter.  Atom is made up of subatomic particles like electrons, protons and neutrons.  Protons and neutrons are present in the nucleus and called nucleons.  Electrons are present in orbitals, outside the nucleus.  During chemical transformations electrons are being exchanged between the elements.  The arrangement of electrons in various atomic or molecular orbital are called electronic configuration.  For example the atomic number of sodium is 11, which means it has 11 electrons.  The electronic configuration of neutral sodium atom is written as given below.

${}_{11}{\text{Na -1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^1$

Electronic configuration indicates the chemical properties and reactivity of the element.

Atomic number is the number of electrons or the number of protons present in that atom. It is the main characteristic of an atom on which most of the properties are dependent.  Mass number is the sum of all the protons and neutrons present in the nucleus.

Answer to Problem 70E

The element is found to be nitrogen and the most stable ion of nitrogen is ${\text{N}}^{3-}$

Explanation of Solution

Atomic number given is $7$. From the periodic table we can identify that the element with atomic number $7$ is nitrogen $\left({}_{\text{7}}\text{N}\right)$.

Nitrogen - $\left[\text{He}\right]{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{3}}$

The valance shell electronic configuration for nitrogen is given above.  From which we can see that if nitrogen is having half filled outer most p orbital. It is easy for nitrogen to gain three electrons than losing the three from the half filled orbit  Hence, the most stable ion of nitrogen will be ${\text{N}}^{3-}$.

(e)

Interpretation Introduction

Interpretation:

From the atomic numbers given, the corresponding elements and their most stable ions has to be identified.

Concept introduction:

Atom is the smallest fundamental unit of matter.  Atom is made up of subatomic particles like electrons, protons and neutrons.  Protons and neutrons are present in the nucleus and called nucleons.  Electrons are present in orbitals, outside the nucleus.  During chemical transformations electrons are being exchanged between the elements.  The arrangement of electrons in various atomic or molecular orbital are called electronic configuration.  For example the atomic number of sodium is 11, which means it has 11 electrons.  The electronic configuration of neutral sodium atom is written as given below.

${}_{11}{\text{Na -1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^1$

Electronic configuration indicates the chemical properties and reactivity of the element.

Atomic number is the number of electrons or the number of protons present in that atom. It is the main characteristic of an atom on which most of the properties are dependent.  Mass number is the sum of all the protons and neutrons present in the nucleus.

Answer to Problem 70E

The element is found to be francium and the most stable ion of francium is ${\text{Fr}}^{\text{+}}$

Explanation of Solution

Atomic number given is $87$. From the periodic table we can identify that the element with atomic number $87$ is Francium $\left({}_{\text{87}}\text{Fr}\right)$.

Francium - $\left[\text{Rn}\right]{\text{ 7s}}^{\text{1}}$

The valance shell electronic configuration for francium is given above From which we can see that if francium  loses one  electron, it acquires inert gas configuration.  Hence, the most stable ion of selenium will be ${\text{Fr}}^{\text{+}}$.

(f)

Interpretation Introduction

Interpretation:

From the atomic numbers given, the corresponding elements and their most stable ions has to be identified.

Concept introduction:

Atom is the smallest fundamental unit of matter.  Atom is made up of subatomic particles like electrons, protons and neutrons.  Protons and neutrons are present in the nucleus and called nucleons.  Electrons are present in orbitals, outside the nucleus.  During chemical transformations electrons are being exchanged between the elements.  The arrangement of electrons in various atomic or molecular orbital are called electronic configuration.  For example the atomic number of sodium is 11, which means it has 11 electrons.  The electronic configuration of neutral sodium atom is written as given below.

${}_{11}{\text{Na -1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^1$

Electronic configuration indicates the chemical properties and reactivity of the element.

Atomic number is the number of electrons or the number of protons present in that atom. It is the main characteristic of an atom on which most of the properties are dependent.  Mass number is the sum of all the protons and neutrons present in the nucleus.

Answer to Problem 70E

The element is found to be bromine and the most stable ion of bromine is ${\text{Br}}^{\text{-}}$

Explanation of Solution

Atomic number given is $35$. From the periodic table we can identify that the element with atomic number $35$ is bromine $\left({}_{35}\text{Br}\right)$.

Bromine- $\left[\text{Ar}\right]{\text{ 3d}}^{\text{10}}{\text{ 4s}}^{\text{2}}{\text{ 4p}}^{\text{5}}$

The electronic configuration for bromine is given above.  From which we can see that it is having a incomplete configuration. If bromine gains one more electron, it acquires completely filled configuration.  Hence, the most stable ion of bromine will be ${\text{Br}}^{\text{-}}$.