2. In this chapter, you will learn to:
Synthesise the atomic structure
Understanding isotopes and their uses
Understanding the electronic structure of an atom
Appreciate the orderliness and uniqueness of the atomic
3. 2.1 ANALYSING MATTER
Describe the particulate nature of matter
Define atoms, molecules and ions
State the kinetic theory of matter
Relate the change in the state of matter to the change in heat.
Relate the change in heat to the change in kinetic energy of
Explain the inter-conversion of the states of matter in terms of
kinetic theory of matter.
An atom is the smallest neutral particle in an element and it
can exist by itself or take part in a chemical reaction.
Copper, Cu, atom is a neutral particle.
The smallest particle in oxygen gas is the oxygen, O, atom.
Copper can exist by itself as copper atoms making up copper
metal or combine with oxygen atoms to form copper(II) oxide,
CuO, through a chemical reaction. Oxygen
atom atom atom
Copper atoms Oxygen gas copper(II) oxide
Molecules are neutral particles, made up of two or more
atoms of the same element or different elements.
Oxygen gas comprises oxygen molecules, O2. each molecules is
made up of 2 oxygen atoms.
Copper(II) oxide, CuO, consist of two different atoms, Cu and O.
Oxygen gas Copper(II) oxide
Ions are particles which are positively or negatively charged.
They are produced when atoms or a group of atoms receive or
Positively-charged ions are called cation, while negatively-
charged particles are called anions.
The ionic compound NaCl
cation – ion with a positive charge
If a neutral atom loses one or more electrons
it becomes a cation.
Na 11 protons 11 protons
11 electrons 10 electrons
anion – ion with a negative charge
If a neutral atom gains one or more electrons
it becomes an anion.
Cl 17 protons 17 protons
17 electrons 18 electrons
13. C) The Kinetic Theory of Matter
The kinetic theory of matter state that matter consists of tiny
and discrete particles that are constantly moving.
This theory has three basic assumptions:
Matter is composed of small particles. These molecules move in
random motion and collide with one another.
There are attractive forces between the molecules when they are
Movements of the particles is affected by heat.
14. D) Change in the state of matter
STATE SOLID LIQUID GAS
Not compact. Loosely
arranged with larger Particles not arranged
Compact and orderly with small
Arrangement spaces between in order. Very far apart
empty spaces between
of particles particles which are in with large empty
contact with one spaces.
Vibrate, rotate and
Vibrate, rotate and
Vibrate and rotate at their fixed move from one point
Movement of move very freely and at
positions. Cannot be to another more freely
particles random. Compressed
compressed. than solid particles.
Cannot be compressed.
Fairly strong but
Very strong weaker than solid Very weak
Higher energy content Highest energy content
Low energy content as
Energy content as particles can move as movement is at
movement is restricted.
When a substances is
heated or cooled its physical
state alters with a
corresponding change in
sublimation, heat is
absorbed by substances. In
all these physical process,
sublimation, heat energy is
released and temperature