Q. 4.81 - An Introduction to General, Organic, and Biological Chemistry

Question

Consider the following atoms in which $X$ represents the chemical symbol of the element:

${}_8{}^{16}X {}_9{}^{16}X {}_{10}{}^{18}X {}_8{}^{17}X {}_8{}^{18}X$

a. What atoms have the same number of protons?

b. Which atoms are isotopes? Of what element?

c. Which atoms have the same mass number?

d. What atoms have the same number of neutrons?

Step-by-Step Solution

Answer

a. The atoms that have the same number of protons are ${}_8{}^{16}X, {}_8{}^{17}X and {}_8{}^{18}X$.

b. The isotopes are ${}_8{}^{16}X, {}_8{}^{17}X and {}_8{}^{18}X$ of the Oxygen atom.

c. The atoms having the same mass number are ${}_8{}^{16}X, {}_9{}^{16}X$ and ${}_{10}{}^{18}X, {}_8{}^{18}X$.

d. The atoms having the same number of neutrons are ${}_8{}^{16}X and {}_{10}{}^{18}X$.

Part (a) Step 1: Given Information

We need to find the atoms which have the same number of protons from given atoms.

Part (a) Step 2: Explanation

Consider the given atoms

${}_8{}^{16}X {}_9{}^{16}X {}_{10}{}^{18}X {}_8{}^{17}X {}_8{}^{18}X$

These are written in the formate ${}_Z{}^{A}X$ in which $A$ is the mass number, $Z$ is the atomic number, and $X$ is the symbol of the atom.

We know that atomic number is the number of protons so ${}_8{}^{16}X, {}_8{}^{17}X and {}_8{}^{18}X$ have the same number of protons.

Part (b) Step 1: Given Information

We need to find the isotopes with the name of the atom.

Part (b) Step 2: Explanation

The atoms that have the same atomic number$\left(Z\right)$ but different mass number$\left(A\right)$ is the called the isotopes.

From the given atoms the isotopes are

${}_8{}^{16}X, {}_8{}^{17}X and {}_8{}^{18}X$

And these are the isotopes of Oxygen$\left(O\right)$ atom.

Part (c) Step 1: Given Information

We need to find the atoms having the same mass number from the given atoms.

Part (c) Step 2: Explanation

Consider the given atoms

${}_8{}^{16}X {}_9{}^{16}X {}_{10}{}^{18}X {}_8{}^{17}X {}_8{}^{18}X$

These are written in the formate ${}_Z{}^{A}X$, where $A$ is the mass number, $Z$ is the atomic number and $X$ is the symbol atom.

The atoms ${}_8{}^{16}X, {}_9{}^{16}X$ and ${}_{10}{}^{18}X, {}_8{}^{18}X$ have the same mass number.

Part (d) Step 1: Given Information

We need to find the atoms having the same number of the neutrons from the given atoms.

Part (d) Step 2: Explanation

The basic formula for the number of neutrons is $A-Z$, where $A$ is the mass number and $Z$ is the atomic number

To find the same number of neutrons we have to find the number of neutrons of all atoms.

For ${}_8{}^{16}X$

Neutrons$=16-8$

$Neutrons=8$

For ${}_9{}^{16}X$

$Neutrons=16-9=7$

For ${}_{10}{}^{18}X$

$Neutrons=18-10=8$

For ${}_8{}^{17}X$

$Neutrons=17-8=9$

And for ${}_8{}^{18}X$

$Neutrons=18-8=10$

Hence, ${}_8{}^{16}X and {}_{10}{}^{18}X$ have the same number of neurons.