Chapter 2, Problem 2.46P

Interpretation Introduction

(a)

Interpretation:

Theelement is to be identified by the given atomic number and mass number. The symbol of this element and number of electrons, protons and neutrons in its atom is to be stated.

Concept Introduction:

The electrons in the atoms revolve around the nucleus in different orbits. The nucleus of the atom has two particles, protons and neutrons. The number of protons is the atomic number and the sum of the protons and neutrons is the mass number of the atom.

Answer to Problem 2.46P

The element with the given atomic number, $Z=10$ and mass number $A=20$ is neon. Its symbol is $\text{Ne}$ . It has $10$ neutrons, $10$ electrons and $10$ protons.

Explanation of Solution

Theelements are organized on the basis of their increasing atomic number in periodic table.

Each atom is assigned a special atomic number. The given atomic number $Z=10$ corresponds to the element, neon. The symbol of neon is the first two letter of its name that is $\text{Ne}$.

The numbers of protons as well as the number of electrons are equal to the atomic number of the element. The atomic number of neon is $10$ .So, the number of electrons and the numbers of protons is $10$.

The formula for mass number of an atom is given below.

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

Substitute the values in the above formula.

  $\begin{array}{c}\text{Mass}\text{number}=\text{Numbers of protons}+\text{Number of neutrons}\\ 20=10+\text{Number of neutrons}\\ \text{Number of neutrons}=20-10\\ =10\end{array}$

Therefore, the number of neutrons is $10$.

Interpretation Introduction

(b)

Interpretation:

The elements is to be identified by the given atomic number and mass number. The symbol of this element and number of electrons, protons and neutrons in its atom is to be stated.

Concept Introduction:

The electrons in the atoms revolve around the nucleus in different orbits. The nucleus of the atom has two particles, protons and neutrons. The number of protons is the atomic number and the sum of the protons and neutrons is the mass number of the atom.

Answer to Problem 2.46P

The element with the given atomic number $Z=13$ and mass number $A=27$ is aluminum. Its symbol is $\text{Al}$ . It has $14$ neutrons, $13$ electrons and $13$ protons.

Explanation of Solution

The elements are organized on the basis of their increasing atomic number in periodic table.

Each atom is assigned a special atomic number. The given atomic number $Z=13$ corresponds to the element,aluminum. The symbol of aluminum is the first two letter of its name that is $\text{Al}$.

The numbers of protons as well asthe number of electrons are equal to the atomic number of the element. The atomic number of Aluminum $Z=13$ , so the number of electrons and the numbers of protons is $13$.

The formula for mass number of an atom is given below.

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

Substitute the values in the above formula.

  $\begin{array}{c}\text{Mass}\text{number}=\text{Numbers of protons}+\text{Number of neutrons}\\ 27=13+\text{Number of neutrons}\\ \text{Number of neutrons}=27-13\\ =14\end{array}$

Therefore, the number of neutrons is $14$.

Interpretation Introduction

(c)

Interpretation:

The element is to be identified by the given atomic number and mass number. The symbol of this element and number of electrons, protons and neutrons in its atom is to be stated.

Concept Introduction:

The electrons in the atoms revolve around the nucleus in different orbits. The nucleus of the atom has two particles, protons and neutrons. The number of protons is the atomic number and the sum of the protons and neutrons is the mass number of the atom.

Answer to Problem 2.46P

The element with the given atomic number $Z=38$ and mass number $A=88$ is strontium. Its symbol is $\text{Sr}$ . It has $50$ neutrons, $38$ electrons and $38$ protons.

Explanation of Solution

The elements are organized on the basis of their increasing atomic number in periodic table.

Each atom is assigned a special atomic number. The given atomic number $Z=38$ corresponds to the element,strontium. The symbol of strontium is the first two letter of its name that is $\text{Sr}$.

The numbers of protons as well asthe number of electrons are equal to the atomic number of the element. The atomic number of strontium $Z=38$ , so the number of electrons and the numbers of protons is $38$.

The formula for mass number of an atom is given below.

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

Substitute the values in theaboveformula.

  $\begin{array}{c}\text{Mass}\text{number}=\text{Numbers of protons}+\text{Number of neutrons}\\ 88=38+\text{Number of neutrons}\\ \text{Number of neutrons}=88-38\\ =50\end{array}$

Therefore, the number of neutrons is $50$.

Interpretation Introduction

(d)

Interpretation:

The elements is to be identified by the given atomic number and mass number. The symbol of this element and number of electrons, protons and neutrons in its atom is to be stated.

Concept Introduction:

The electrons in the atoms revolve around the nucleus in different orbits. The nucleus of the atom has two particles, protons and neutrons. The number of protons is the atomic number and the sum of the protons and neutrons is the mass number of the atom.

Answer to Problem 2.46P

The element with the given atomic number $Z=55$ and mass number $A=133$ is cesium. Its symbol is $\text{Cs}$ . It has $78$ neutrons, $55$ electrons and $55$ protons.

Explanation of Solution

The elements are organized on the basis of their increasing atomic number in periodic table.

Each atom is assigned a special atomic number. The given atomic number $Z=55$ corresponds to the element,cesium. The symbol of cesium is the first two letter of its name that is $\text{Cs}$.

The numbers of protons as well asthe number of electrons are equal to the atomic number of the element. The atomic number of cesium is $Z=55$ , so the number of electrons and the numbers of protons is $55$.

The formula for mass number of an atom is given below.

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

Substitute the values in theabove formula.

  $\begin{array}{c}\text{Mass}\text{number}=\text{Numbers of protons}+\text{Number of neutrons}\\ 133=55+\text{Number of neutrons}\\ \text{Number of neutrons}=133-55\\ =78\end{array}$

Therefore, the number of neutrons is $78$.

Interpretation Introduction

(e)

Interpretation:

The elements is to be identified by the given atomic number and mass number. The symbol of this element and number of electrons, protons and neutrons in its atom is to be stated.

Concept Introduction:

The electrons in the atoms revolve around the nucleus in different orbits. The nucleus of the atom has two particles, protons and neutrons. The number of protons is the atomic number and the sum of the protons and neutrons is the mass number of the atom.

Answer to Problem 2.46P

The element with the given atomic number $Z=28$ and mass number $A=59$ is nickel. Its symbol is $\text{Ni}$ . It has $31$ neutrons, $28$ electrons and $28$ protons.

Explanation of Solution

The elements are organized on the basis of their increasing atomic number in periodic table.

Each atom is assigned a special atomic number. The given atomic number $Z=28$ corresponds to the element,nickel. The symbol of nickel is the first two letter of its name that is $\text{Ni}$.

The numbers of protons as well asthe number of electrons are equal to the atomic number of the element. The atomic number of Nickel $Z=28$ , so the number of electrons and the numbers of protons is $28$.

The formula for mass number of an atom is given below.

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

Substitute the values in theabove formula.

  $\begin{array}{c}\text{Mass}\text{number}=\text{Numbers of protons}+\text{Number of neutrons}\\ 58=28+\text{Number of neutrons}\\ \text{Number of neutrons}=59-28\\ =31\end{array}$

Therefore, the number of neutrons is $31$.

Interpretation Introduction

(f)

Interpretation:

The elements is to be identified by the given atomic number and mass number. The symbol of this element and number of electrons, protons and neutrons in its atom is to be stated.

Concept Introduction:

The electrons in the atoms revolve around the nucleus in different orbits. The nucleus of the atom has two particles, protons and neutrons. The number of protons is the atomic number and the sum of the protons and neutrons is the mass number of the atom.

Answer to Problem 2.46P

The element with the given atomic number $Z=79$ and mass number $A=197$ is gold. Its symbol is $\text{Au}$ . It has $118$ neutrons, $79$ electrons and $79$ protons.

Explanation of Solution

The elements are organized on the basis of their increasing atomic number in periodic table.

Each atom is assigned a special atomic number. The given atomic number $Z=79$ corresponds to the element,gold. The symbol of gold is the first two letter of its Latin name aurum that is $\text{Au}$.

The numbers of protons as well as the number of electrons are equal to the atomic number of the element. The atomic number $Z=79$ , so the number of electrons and the numbers of protons is $79$.

The formula for mass number of an atom is given below.

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

Substitute the values in theabove formula.

  $\begin{array}{c}\text{Mass}\text{number}=\text{Numbers of protons}+\text{Number of neutrons}\\ 197=79+\text{Number of neutrons}\\ \text{Number of neutrons}=197-79\\ =118\end{array}$

Therefore, the number of neutrons is $118$.