Chapter 2.3, Problem 2.3P

(a)

Interpretation Introduction

Interpretation:

The symbol of both the isotopes of bromine should be identified.

Concept Introduction:

Atoms with same atomic numbers but different mass numbers are called isotopes.

Mass number (A):

The atom’s mass number (A) is calculated from protons and neutrons in an atom

Atomic number can be calculated as follows.

$\text{Atomic number = Mass number - Neutron’s}$

(b)

Interpretation Introduction

Interpretation:

The molecular weight be calculated.

Concept Introduction:

The atomic weight can be calculated using following formula,

$\text{Atomic weight = }{\displaystyle \sum \text{(isotopic abundance) }\times \text{(isotopic mass)}}$