Chapter 2, Problem 2.40QE

(a)

Interpretation Introduction

Interpretation:

Symbol of atom or ion has to be written that has 23 protons, 28 neutrons, and 20 electrons.

Concept Introduction:

Each and every element present in the Periodic table has a unique name.  Some of the elements are named considering their atomic number.  In order to represent the elements in a short form, atomic symbols are used.  Generally the first two letters of the element name will be used as symbol where the first letter is in upper case.

Chemical names are represented as atomic symbols.  In the symbols, the mass number and atomic number are shown.  The complete symbol for an element can be represented as shown below.

Atomic number is the total number of protons present in the atom of an element.  Mass number is the total number of protons and neutrons present in nucleus of an atom.

Explanation of Solution

The species is said to contain 23 protons, 28 neutrons, and 20 electrons.  Atomic number is equal to the number of protons and mass number is equal to the sum of protons and neutrons.  Atomic number and mass number can be given as shown below.

    $\begin{array}{c}\text{Atomic}\text{number}=\text{Number}\text{of}\text{protons}\\ =23\\ \text{Mass}\text{number}=\text{Number}\text{of}\text{protons+Number}\text{of}\text{neutrons}\\ =23+28\\ =51\end{array}$

The charge on the ion can be calculated considering the number of protons and electrons as shown below.

    $\begin{array}{c}\text{Charge}=\text{Number}\text{of}\text{protons}-\text{Number}\text{of}\text{electrons}\\ \text{=23}-20\\ =+3\end{array}$

Element with the atomic number of 23 is vanadium.  The atomic symbol of ion can be given as $\text{V}{}^{3+}$.

(b)

Interpretation Introduction

Interpretation:

Symbol of atom or ion has to be written that has 53 protons, 74 neutrons, and 54 electrons.

Concept Introduction:

Refer part (a).

Explanation of Solution

The species is said to contain 53 protons, 74 neutrons, and 54 electrons.  Atomic number is equal to the number of protons and mass number is equal to the sum of protons and neutrons.  Atomic number and mass number can be given as shown below.

    $\begin{array}{c}\text{Atomic}\text{number}=\text{Number}\text{of}\text{protons}\\ =53\\ \text{Mass}\text{number}=\text{Number}\text{of}\text{protons+Number}\text{of}\text{neutrons}\\ =53+74\\ =127\end{array}$

The charge on the ion can be calculated considering the number of protons and electrons as shown below.

    $\begin{array}{c}\text{Charge}=\text{Number}\text{of}\text{protons}-\text{Number}\text{of}\text{electrons}\\ \text{=53}-54\\ =-1\end{array}$

Element with the atomic number of 53 is iodine.  The atomic symbol of ion can be given as $\text{I}{}^{-}$.

(c)

Interpretation Introduction

Interpretation:

Symbol of atom or ion has to be written that has 44 protons, 58 neutrons, and 41 electrons.

Concept Introduction:

Refer part (a).

Explanation of Solution

The species is said to contain 44 protons, 58 neutrons, and 41 electrons.  Atomic number is equal to the number of protons and mass number is equal to the sum of protons and neutrons.  Atomic number and mass number can be given as shown below.

    $\begin{array}{c}\text{Atomic}\text{number}=\text{Number}\text{of}\text{protons}\\ =44\\ \text{Mass}\text{number}=\text{Number}\text{of}\text{protons+Number}\text{of}\text{neutrons}\\ =44+58\\ =102\end{array}$

The charge on the ion can be calculated considering the number of protons and electrons as shown below.

    $\begin{array}{c}\text{Charge}=\text{Number}\text{of}\text{protons}-\text{Number}\text{of}\text{electrons}\\ \text{=44}-41\\ =+3\end{array}$

Element with the atomic number of 44 is ruthenium.  The atomic symbol of ion can be given as $\text{R}{\text{u}}^{\text{3+}}$.

(d)

Interpretation Introduction

Interpretation:

Symbol of atom or ion has to be written that has 15 protons, 16 neutrons, and 15 electrons.

Concept Introduction:

Refer part (a).

Explanation of Solution

The species is said to contain 15 protons, 16 neutrons, and 15 electrons.  Atomic number is equal to the number of protons and mass number is equal to the sum of protons and neutrons.  Atomic number and mass number can be given as shown below.

    $\begin{array}{c}\text{Atomic}\text{number}=\text{Number}\text{of}\text{protons}\\ =15\\ \text{Mass}\text{number}=\text{Number}\text{of}\text{protons+Number}\text{of}\text{neutrons}\\ =15+16\\ =31\end{array}$

The charge on the ion can be calculated considering the number of protons and electrons as shown below.

    $\begin{array}{c}\text{Charge}=\text{Number}\text{of}\text{protons}-\text{Number}\text{of}\text{electrons}\\ \text{=15}-15\\ =0\end{array}$

As the charge is zero, this is an atom and not an ion.

Element with the atomic number of 15 is phosphorus.  The atomic symbol of atom can be given as $\text{P}$.