Chapter 4.3, Problem 30LC

Interpretation Introduction

Interpretation : The atomic number and mass number differences are to be compared.

Concept Introduction : The count of protons present in the nucleus of the atom gives the atomic number. The count of protons and neutrons present in the nucleus of the atom gives the mass number.

Answer to Problem 30LC

The mass number is the sum of the atomic number and number of neutrons for an element.

The difference in mass number and atomic number is the number of neutrons present in the element.

Explanation of Solution

The count of protons present in the nucleus of the atom gives the atomic number. The symbol used to represent the atomic number is Z.

The count of protons and neutrons present in the nucleus of the atom gives the mass number. The symbol used to represent the mass number is A.

The number of protons, number of electrons, and atomic number are always equal for an element.

The mass number is the sum of the atomic number and number of neutrons for an element.

The difference in mass number and atomic number is the number of neutrons present in the element.

The formula to calculate the mass number is given as:

  $\text{Mass number}\text{=}\text{Atomic number}-\text{Number of neutrons}$