Chapter 3, Problem 3.26EP

(a)

Interpretation Introduction

Interpretation:

$\text{A}\text{r}$ and $\text{C}\text{a}$ has to be characterized as they have same number of neutrons or same number of protons or same number of nucleons or same total number of subatomic particles.

Concept Introduction:

Atoms are made up of even smaller particles.  These particles are very small and these are all the building blocks of atoms and they are known as subatomic particles.  Protons, electrons, and neutrons are the subatomic particles that are found in atom.  Electrons possess a negative electrical charge.  Protons possess a positive electrical charge.  Neutrons possess no charge and they are neutral.

Atomic number for each and every element is a unique one.  This is the total number of protons that is present in an atom.  As the atom is electrically neutral, it can also be said that the total number of electrons is the atomic number.  Atomic number is represented by the symbol Z.

$\text{Atomic number}\text{=}\text{number of protons}\text{=}\text{number of electrons}$

Mass number is the sum of the number of protons and neutrons inside the nucleus of an atom.  This gives the number of subatomic particle present inside the nucleus.  Mass number is represented by the symbol A.

$\text{Mass number}\text{=}\text{number of protons}\text{+}\text{number of neutrons}$

From atomic number and mass number, the number of each sub atomic particle can be found.

$\begin{array}{l}\text{Number of protons}\text{=}\text{Atomic number}\text{=}Z\\ \text{Number of electrons}\text{=}\text{Atomic number}\text{=}Z\\ \text{Number of neutrons}\text{=}\text{Mass}\text{number - Atomic number}\text{=}A-Z\end{array}$

Complete chemical symbol notation can be given as.

An element is a pure substance that cannot be broken by ordinary chemical reactions into simpler substances.  All the atoms in an element will have the same atomic number.  The electrons only take part in the chemical reaction while the nucleus does not.  Hence, the atomic number (number or protons) does not change and it characterizes an atom.

Explanation of Solution

For $\text{A}\text{r}$:

The atomic number is given as 18.  The element is found to be argon.  Mass number given for argon is given as 40.  The number of protons present in it is also 18 as atomic number is the number of protons or electrons.  Mass number of the sum of protons and neutrons present in the atom.

The number of neutrons can be identified by finding the difference between mass number and atomic number.  This gives the number of neutrons to be 22.

The total number of nucleons is same as that of the mass number.  This means the total number of nucleons is 40.

The total number of subatomic particle present in the given atom is the sum of mass number and atomic number.  This means the total number of subatomic particle is 58.

For $\text{C}\text{a}$:

The atomic number is given as 20.  The element is found to be calcium.  Mass number given for calcium is given as 40.  The number of protons present in it is also 20 as atomic number is the number of protons or electrons.  Mass number of the sum of protons and neutrons present in the atom.

The number of neutrons can be identified by finding the difference between mass number and atomic number.  This gives the number of neutrons to be 20.

The total number of nucleons is same as that of the mass number.  This means the total number of nucleons is 40.

The total number of subatomic particle present in the given atom is the sum of mass number and atomic number.  This means the total number of subatomic particle is 60.

On comparing both the pair of atoms it is found that they contain same number of nucleons only.

(b)

Interpretation Introduction

Interpretation:

$\text{N}$ and $\text{N}$ has to be characterized as they have same number of neutrons or same number of protons or same number of nucleons or same total number of subatomic particles.

Concept Introduction:

Atoms are made up of even smaller particles.  These particles are very small and these are all the building blocks of atoms and they are known as subatomic particles.  Protons, electrons, and neutrons are the subatomic particles that are found in atom.  Electrons possess a negative electrical charge.  Protons possess a positive electrical charge.  Neutrons possess no charge and they are neutral.

Atomic number for each and every element is a unique one.  This is the total number of protons that is present in an atom.  As the atom is electrically neutral, it can also be said that the total number of electrons is the atomic number.  Atomic number is represented by the symbol Z.

$\text{Atomic number}\text{=}\text{number of protons}\text{=}\text{number of electrons}$

Mass number is the sum of the number of protons and neutrons inside the nucleus of an atom.  This gives the number of subatomic particle present inside the nucleus.  Mass number is represented by the symbol A.

$\text{Mass number}\text{=}\text{number of protons}\text{+}\text{number of neutrons}$

From atomic number and mass number, the number of each sub atomic particle can be found.

$\begin{array}{l}\text{Number of protons}\text{=}\text{Atomic number}\text{=}Z\\ \text{Number of electrons}\text{=}\text{Atomic number}\text{=}Z\\ \text{Number of neutrons}\text{=}\text{Mass}\text{number - Atomic number}\text{=}A-Z\end{array}$

Complete chemical symbol notation can be given as.

An element is a pure substance that cannot be broken by ordinary chemical reactions into simpler substances.  All the atoms in an element will have the same atomic number.  The electrons only take part in the chemical reaction while the nucleus does not.  Hence, the atomic number (number or protons) does not change and it characterizes an atom.

Explanation of Solution

For $\text{N}$:

The atomic number is given as 7.  The element is found to be nitrogen.  Mass number given for nitrogen is given as 14.  The number of protons present in it is also 7 as atomic number is the number of protons or electrons.  Mass number of the sum of protons and neutrons present in the atom.

The number of neutrons can be identified by finding the difference between mass number and atomic number.  This gives the number of neutrons to be 7.

The total number of nucleons is same as that of the mass number.  This means the total number of nucleons is 14.

The total number of subatomic particle present in the given atom is the sum of mass number and atomic number.  This means the total number of subatomic particle is 21.

For $\text{N}$:

The atomic number is given as 7.  The element is found to be nitrogen.  Mass number given for nitrogen is given as 15.  The number of protons present in it is also 7 as atomic number is the number of protons or electrons.  Mass number of the sum of protons and neutrons present in the atom.

The number of neutrons can be identified by finding the difference between mass number and atomic number.  This gives the number of neutrons to be 8.

The total number of nucleons is same as that of the mass number.  This means the total number of nucleons is 15.

The total number of subatomic particle present in the given atom is the sum of mass number and atomic number.  This means the total number of subatomic particle is 22.

On comparing both the pair of atoms it is found that they contain same number of protons.

(c)

Interpretation Introduction

Interpretation:

$\text{C}$ and $\text{N}$ has to be characterized as they have same number of neutrons or same number of protons or same number of nucleons or same total number of subatomic particles.

Concept Introduction:

Atoms are made up of even smaller particles.  These particles are very small and these are all the building blocks of atoms and they are known as subatomic particles.  Protons, electrons, and neutrons are the subatomic particles that are found in atom.  Electrons possess a negative electrical charge.  Protons possess a positive electrical charge.  Neutrons possess no charge and they are neutral.

Atomic number for each and every element is a unique one.  This is the total number of protons that is present in an atom.  As the atom is electrically neutral, it can also be said that the total number of electrons is the atomic number.  Atomic number is represented by the symbol Z.

$\text{Atomic number}\text{=}\text{number of protons}\text{=}\text{number of electrons}$

Mass number is the sum of the number of protons and neutrons inside the nucleus of an atom.  This gives the number of subatomic particle present inside the nucleus.  Mass number is represented by the symbol A.

$\text{Mass number}\text{=}\text{number of protons}\text{+}\text{number of neutrons}$

From atomic number and mass number, the number of each sub atomic particle can be found.

$\begin{array}{l}\text{Number of protons}\text{=}\text{Atomic number}\text{=}Z\\ \text{Number of electrons}\text{=}\text{Atomic number}\text{=}Z\\ \text{Number of neutrons}\text{=}\text{Mass}\text{number - Atomic number}\text{=}A-Z\end{array}$

Complete chemical symbol notation can be given as.

An element is a pure substance that cannot be broken by ordinary chemical reactions into simpler substances.  All the atoms in an element will have the same atomic number.  The electrons only take part in the chemical reaction while the nucleus does not.  Hence, the atomic number (number or protons) does not change and it characterizes an atom.

Explanation of Solution

For $\text{C}$:

The atomic number is given as 6.  The element is found to be carbon.  Mass number given for carbon is given as 14.  The number of protons present in it is also 6 as atomic number is the number of protons or electrons.  Mass number of the sum of protons and neutrons present in the atom.

The number of neutrons can be identified by finding the difference between mass number and atomic number.  This gives the number of neutrons to be 8.

The total number of nucleons is same as that of the mass number.  This means the total number of nucleons is 14.

The total number of subatomic particle present in the given atom is the sum of mass number and atomic number.  This means the total number of subatomic particle is 22.

For $\text{N}$:

The atomic number is given as 7.  The element is found to be nitrogen.  Mass number given for nitrogen is given as 15.  The number of protons present in it is also 7 as atomic number is the number of protons or electrons.  Mass number of the sum of protons and neutrons present in the atom.

The number of neutrons can be identified by finding the difference between mass number and atomic number.  This gives the number of neutrons to be 8.

The total number of nucleons is same as that of the mass number.  This means the total number of nucleons is 15.

The total number of subatomic particle present in the given atom is the sum of mass number and atomic number.  This means the total number of subatomic particle is 22.

On comparing both the pair of atoms it is found that they contain same number of neutrons.

(d)

Interpretation Introduction

Interpretation:

$\text{A}\text{r}$ and $\text{K}$ has to be characterized as they have same number of neutrons or same number of protons or same number of nucleons or same total number of subatomic particles.

Concept Introduction:

Atoms are made up of even smaller particles.  These particles are very small and these are all the building blocks of atoms and they are known as subatomic particles.  Protons, electrons, and neutrons are the subatomic particles that are found in atom.  Electrons possess a negative electrical charge.  Protons possess a positive electrical charge.  Neutrons possess no charge and they are neutral.

Atomic number for each and every element is a unique one.  This is the total number of protons that is present in an atom.  As the atom is electrically neutral, it can also be said that the total number of electrons is the atomic number.  Atomic number is represented by the symbol Z.

$\text{Atomic number}\text{=}\text{number of protons}\text{=}\text{number of electrons}$

Mass number is the sum of the number of protons and neutrons inside the nucleus of an atom.  This gives the number of subatomic particle present inside the nucleus.  Mass number is represented by the symbol A.

$\text{Mass number}\text{=}\text{number of protons}\text{+}\text{number of neutrons}$

From atomic number and mass number, the number of each sub atomic particle can be found.

$\begin{array}{l}\text{Number of protons}\text{=}\text{Atomic number}\text{=}Z\\ \text{Number of electrons}\text{=}\text{Atomic number}\text{=}Z\\ \text{Number of neutrons}\text{=}\text{Mass}\text{number - Atomic number}\text{=}A-Z\end{array}$

Complete chemical symbol notation can be given as.

An element is a pure substance that cannot be broken by ordinary chemical reactions into simpler substances.  All the atoms in an element will have the same atomic number.  The electrons only take part in the chemical reaction while the nucleus does not.  Hence, the atomic number (number or protons) does not change and it characterizes an atom.

Explanation of Solution

For $\text{A}\text{r}$:

The atomic number is given as 18.  The element is found to be argon.  Mass number given for argon is given as 38.  The number of protons present in it is also 18 as atomic number is the number of protons or electrons.  Mass number of the sum of protons and neutrons present in the atom.

The number of neutrons can be identified by finding the difference between mass number and atomic number.  This gives the number of neutrons to be 20.

The total number of nucleons is same as that of the mass number.  This means the total number of nucleons is 38.

The total number of subatomic particle present in the given atom is the sum of mass number and atomic number.  This means the total number of subatomic particle is 56.

For $\text{K}$:

The atomic number is given as 19.  The element is found to be potassium.  Mass number given for potassium is given as 39.  The number of protons present in it is also 19 as atomic number is the number of protons or electrons.  Mass number of the sum of protons and neutrons present in the atom.

The number of neutrons can be identified by finding the difference between mass number and atomic number.  This gives the number of neutrons to be 20.

The total number of nucleons is same as that of the mass number.  This means the total number of nucleons is 39.

The total number of subatomic particle present in the given atom is the sum of mass number and atomic number.  This means the total number of subatomic particle is 58.

On comparing both the pair of atoms it is found that they contain same number of neutrons.