The document is a study guide covering the structure of the atom including: 1) Matter is made up of elementary particles like atoms, molecules, and ions. Atoms are the basic unit that make up elements. 2) The structure of an atom includes subatomic particles like protons, neutrons, and electrons. Protons and neutrons are located in the nucleus while electrons surround it in shells. 3) Atoms are classified by their proton number and nucleon number. The electronic configuration determines an element's properties. 4) Elements are arranged in the periodic table based on their atomic structure. This allows prediction of an element's physical and chemical properties.

1. Name:…………………………………….. Form:…………………. Date:………………
TOPIC 2 : THE STRUCTURE OF THE ATOM
MATTER Refer : Text book pg 11
1. Matter is anything that occupies …………… and has ………….
2. The particle theory of matter states that matter is made up of ………….. and …………….particles.
3. Elementary particles that make up matter may be …………….., ……………. or ………….
• An atom is the ……………neutral particle of an element that can participate in a chemical reaction.
• A molecule is a neutral particle made up of either atoms of the same element or atoms of different
elements.
• An ion is a ……………… or ………………particle which consists of either one atom or atoms from
different element.
4. The classifications of matter include ………………… and …………………..
5. (a) An element is a substance that cannot be separated into simpler substances by chemical means.
It consists of only one type of ………..
The particles of an element may be ………………. or…………………..
(b) The elements can be divided into three categories:
(i) metals for examples sodium, magnesium, copper and etc
(ii) nonmetals for examples hydrogen, chlorine, bromine and etc
(iii) metalloids for examples boron, silicon and etc
5. A compound is a substance that contains ………….. or more ……………. that are chemically bonded
together.
A compound is made up of either ………………. or ………………
6. Compounds can be divided into two categories :
(i) covalent compound: particles : …………………, ex: water, carbon dioxide
(formed between a nonmetal atom and a nonmetal)
(ii) ionic compound: particles :………………….ion and ……………………….ion
(formed between a metal atom and nonmetal atom)
7. Complete the diagram below:
(Element, Nonmetal, Ion, Atom, Molecule)
MATTER
Compound
Categories Metal Covalent
Particle Molecule

2. Subatomic Particles of an Atom Refer : Text book pg 17
1. Complete the table below that shows the properties of the subatomic particles:
Subatomic Symbol Relative Relative Location in an * Real charge / C * Real mass / kg
particles charge mass atom
Proton +1.60 X 10-19 1.673 X 10-27
Neutron 0 (neutral) 1.675 X 10-27
Electron -1.60 X 10-19 9.11 X 10-31
2. In a neutral atom, the number of ……………….is the same as the number of ……………..
3. As the mass of protons and neutrons are greater than electrons, most of the mass of an atom is concentrated in
the …………….
Proton Number and Nucleon Number Refer : Text book pg 18
1. Atoms of same element have same number of ………………...
2. The proton number of an element is the number of ……………..in its atom.
3. The nucleon number of an element is the total number of ……………….. and ………………in its atom.
Nucleon number = Number of protons + Number of neutrons
4. The standard representation for an atom:
X
Nucleon number A
Symbol of elements
A
Proton number Z
The Electronic Structure of an Atom Refer : Text book pg 22
1. Electrons are arranged around the nucleus in the shells of an atom.
2. Each shell can occupy a certain number of electrons.
Maximum
Shell number of
electrons
First
Second
Third
Fourth
3. The electrons in the outermost shell are called the ………………… electrons.
Example: The atomic structure of an aluminium
27
Al
13
p = 13 Al
e = 13, electrons arrangement, 2.8.3
n = 14

3. The Atomic Structure Refer : Text book pg 18-22, 60-63
Complete the table below:
No. Element Symbol Proton Nucleon Number Electron Group Period Metal
of number number of arrangement /Metalloid /
element p n e Nonmetal
1 Hydrogen 1 1
2 Helium 2 4
3 Lithium 3 7
4 Beryllium 4 9
5 Boron 5 11
6 Carbon 6 12
7 Nitrogen 7 14
8 Oxygen 8 16
9 Fluorine 9 19
10 Neon 10 20
11 Sodium 11 23
12 Magnesium 12 24
13 Aluminium 13 27
14 Silicon 14 28
15 Phosphorus 15 31
16 Sulphur 16 32
17 Chlorine 17 35
18 Argon 18 40
19 Potassium 19 39
20 Calcium 20 40
Attention :
1. To decide the position of the Group, Period, metals and non-metals of an element in the Periodic Table, please
refer to page 63 (text book) in Chapter 4, Periodic Table of Elements.
2. There are 18 groups of elements in the Periodic Table; Group 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
17, and 18
3. There are 7 periods in the Periodic Table: Period 1, 2, 3, 4, 5, 6 and 7
4. The nucleon number of an atom does not have to be memorized.
Exercise

4. Based on the examples of the atomic structure of an aluminium and the table above, draw the atomic structure for 12
first elements in the Periodic Table of Elements beginning from the hydrogen until magnesium.