Chapter 2.3, Problem 2CP

Interpretation Introduction

Interpretation:

The mass number of an oxygen atom having nine neutrons in its nucleusis to be determined

Concept introduction:

The atomic number $(Z)$ is the number of protons in the nucleus of each atom of an element. It also indicates the number of electrons in an atom. Mathematically, it can be represented as follows:

$\text{Atomic number}(Z)=\text{ No}\text{. of electrons or protons}$

Mass number $(A)$ is the total number of protons and neutrons present in the nucleus of an atom of an element. Mathematically, it can be represented as follows:

$\text{Mass number}(A)=\text{ No}\text{. of protons (Z) + No}\text{. of neutrons}$

The atomic number and mass number of the element with symbol X are represented as follows:

${}_{\text{Z}}^{\text{A}}\text{X}$

Here, A is the mass number $\left(\text{number of protons + number of neutrons}\right)$, Z is the atomic number $\left(\text{number of protons}\right)$, and X is the element’s symbol.