Chapter 2, Problem 23P

Interpretation Introduction

(a)

Interpretation:

The number of neutrons and protons in the isotope of $\text{N}\text{e}$ should be determined.

Concept Introduction:

Isotopes have same number of protons but different number of neutrons. In an atom, mass number is equal to the sum of total number of protons and neutrons and atomic number is equal to number of protons.

Answer to Problem 23P

The number of protons is equal to atomic number. In Periodic Table, the atomic number of neon is 10. Therefore, the isotope of $\text{N}\text{e}$ has 10 protons and 12 neutrons.

Explanation of Solution

Isotopes have same number of protons but different number of neutrons. Mass number is the sum of number of protons and neutrons in an atom. The number of protons is equal to atomic number therefore, each neon atom has 10 protons.

$\begin{array}{c}{\text{ A = n}}_p{\text{ + n}}_n\\ {\text{22 = 10 + n}}_n\\ {\text{ n}}_n\text{= 22 - 10}\\ {\text{ n}}_n\text{= 12}\end{array}$

Therefore, the isotope of $\text{N}\text{e}$ has 10 protons and 12 neutrons.

Interpretation Introduction

(b)

Interpretation:

The number of neutrons and protons in the isotope of $Pd$ should be determined.

Concept Introduction:

Isotopes have same number of protons but different number of neutrons. In an atom, mass number is equal to the sum of total number of protons and neutrons and atomic number is equal to number of protons.

Answer to Problem 23P

The number of protons is equal to atomic number. In Periodic Table, the atomic number of palladium is 46. Therefore, the isotope of $Pd$ has 46 protons and 58 neutrons.

Explanation of Solution

Isotopes have same number of protons but different number of neutrons. Mass number is the sum of number of protons and neutrons in an atom. The number of protons is equal to atomic number therefore, each palladium atom has 46 protons.

$\begin{array}{c}{\text{A = n}}_p{\text{+ n}}_n\\ {\text{104 = 46 + n}}_n\\ {\text{ n}}_n\text{ = 104 - 46}\\ {\text{ n}}_n\text{ = 58}\end{array}$

Therefore, the isotope of $Pd$ has 46 protons and 58 neutrons.

Interpretation Introduction

(c)

Interpretation:

The number of neutrons and protons in the isotope of $\text{C}\text{l}$ should be determined.

Concept Introduction:

Isotopes have same number of protons but different number of neutrons. In an atom, mass number is equal to the sum of total number of protons and neutrons and atomic number is equal to number of protons.

Answer to Problem 23P

The number of protons is equal to atomic number. In Periodic Table, the atomic number of chlorine is 17. Therefore, the isotope of $\text{C}\text{l}$ has 17 protons and 18 neutrons.

Explanation of Solution

Isotopes have same number of protons but different number of neutrons. Mass number is the sum of number of protons and neutrons in an atom. The number of protons is equal to atomic number therefore, each chlorine atom has 17 protons.

$\begin{array}{c}{\text{A = n}}_p{\text{ + n}}_n\\ {\text{35 = 17 + n}}_n\\ {\text{ n}}_n\text{ = 35 - 17}\\ {\text{ n}}_n\text{ = 18}\end{array}$

Therefore, the isotope of $\text{C}\text{l}$ has 17 protons and 18 neutrons.

Interpretation Introduction

(d)

Interpretation:

The number of neutrons and protons in the isotope of Tellurium-128 should be determined.

Concept Introduction:

Isotopes have same number of protons but different number of neutrons. In an atom, mass number is equal to the sum of total number of protons and neutrons and atomic number is equal to number of protons.

Answer to Problem 23P

The number of protons is equal to atomic number. In Periodic Table, the atomic number of tellurium is 52. Therefore, the isotope of tellurium-128 has 52 protons and 76 neutrons.

Explanation of Solution

Isotopes have same number of protons but different number of neutrons. Mass number is the sum of number of protons and neutrons in an atom. The number of protons is equal to atomic number therefore, each tellurium atom has 52 protons.

$\begin{array}{c}{\text{A = n}}_p{\text{ + n}}_n\\ {\text{128 = 52 + n}}_n\\ {\text{n}}_n\text{ = 128 - 52}\\ {\text{n}}_n\text{ = 76}\end{array}$

Therefore, the isotope of tellurium-128 has 52 protons and 76 neutrons.

Interpretation Introduction

(e)

Interpretation:

The number of neutrons and protons in the isotope of Lithium-7 should be determined.

Concept Introduction:

Isotopes have same number of protons but different number of neutrons. In an atom, mass number is equal to the sum of total number of protons and neutrons and atomic number is equal to number of protons.

Answer to Problem 23P

The number of protons is equal to atomic number. In Periodic Table, the atomic number of lithium is 3. Therefore, the isotope of lithium-7 has 3 protons and 4 neutrons.

Explanation of Solution

Isotopes have same number of protons but different number of neutrons. Mass number is the sum of number of protons and neutrons in an atom. The number of protons is equal to atomic number therefore, each lithium atom has 3 protons.

$\begin{array}{c}{\text{A = n}}_p{\text{ + n}}_n\\ {\text{ 7 = 3 + n}}_n\\ {\text{n}}_n\text{= 7 - 3}\\ {\text{n}}_n\text{= 4}\end{array}$

Therefore, the isotope of lithium-7 has 3 protons and 4 neutrons.

Interpretation Introduction

(f)

Interpretation:

The number of neutrons and protons in the isotope of Uranium-238 should be determined.

Concept Introduction:

Isotopes have same number of protons but different number of neutrons. In an atom, mass number is equal to the sum of total number of protons and neutrons and atomic number is equal to number of protons.

Answer to Problem 23P

The number of protons is equal to atomic number. In Periodic Table, the atomic number of uranium is 92. Therefore, the isotope of uranium-238 has 92 protons and 146 neutrons.

Explanation of Solution

Isotopes have same number of protons but different number of neutrons. Mass number is the sum of number of protons and neutrons in an atom. The number of protons is equal to atomic number therefore, each uranium atom has 92 protons.

$\begin{array}{c}{\text{A = n}}_p{\text{ + n}}_n\\ \text{238}={\text{ 92 + n}}_n\\ {\text{n}}_n\text{= 238 - 92}\\ {\text{n}}_n\text{ = 146}\end{array}$

Therefore, the isotope of uranium-238 has 92 protons and 146 neutrons.