THE STRUCTURE OF THE ATOM

Chapter 2

In this chapter, you will learn to:

Analyse matterSynthesise the atomic structure

Understanding isotopes and their usesUnderstanding the electronic structure of an atomAppreciate the orderliness and uniqueness of the atomic

structure.

2.3 IsotopesThe atoms of the same element with the same number of

protons but a different number of neutrons.

Isotopes of a particular element have the same chemical properties because they have the same number of electrons.

Isotopes of a particular element have different physical properties because they have a different number of neutrons in each. Thus their densities and boiling points are different.

The relative atomic mass of an element is the average mass of all the isotopes of that element.

The uses of Isotopes

2.4 The Electronic Structure of an Atom

Shell Maximum number of electrons

1st 2

2nd 8

3rd 8 or 18

4th 36