This chapter discusses the structure of the atom, including analyzing matter, synthesizing atomic structure, understanding isotopes and their uses, and appreciating the orderliness and uniqueness of atomic structure. Isotopes of the same element have the same number of protons but different numbers of neutrons. While isotopes have the same chemical properties due to their identical number of electrons, they have different physical properties because of varying neutron counts. The electronic structure of an atom is organized into shells, with the first shell holding up to 2 electrons and higher shells able to accommodate more electrons in set numbers.

1. THE STRUCTURE OF
THE ATOM
Chapter 2

2. In this chapter, you will learn to:
Analyse matter
Synthesise the atomic structure
Understanding isotopes and their uses
Understanding the electronic structure of an atom
Appreciate the orderliness and uniqueness of the atomic
structure.

3. 2.3 Isotopes
The atoms of the same element with the same number of
protons but a different number of neutrons.

7. 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.

8. The uses of Isotopes

9. 2.4 The Electronic Structure of
an Atom
Shell Maximum number of electrons
1st 2
2nd 8
3rd 8 or 18
4th 36