Chapter 2 of the chemistry document covers the concepts of atoms, elements, compounds, and the periodic table. Atoms are the fundamental particles of matter, while elements consist of only one type of atom; compounds are formed from two or more different elements. The periodic table organizes elements by atomic number and provides information on their characteristics, including atomic and nucleon numbers, electron configuration, and valency.

1. WRP:
CHEMISTRY
CHAPTER 2: ATOMS AND ELEMENTS
SANAVI NAIK
IGCSE 1

2. AGENDA
ATOMS, ELEMENTS,
COMPOUNDS, MOLECULES
THE PERIODIC TABLE
ATOMIC NUMBER, NUCLEON
NUMBER
ELECTRONIC CONFIGURATION
VALENCY
VALENCE ELECTRONS
NAMING CHEMICAL
COMPOUNDS

3. ATOMS, ELEMENTS,
COMPOUNDS, MOLECULES
ATOMS ELEMENTS COMPOUNDS MOLECULES
Atoms are the
smallest particles
of matter that we
cannot break
down further by
chemical means.
It contains
protons, neutrons
and electrons.
Elements are only
one type of
atoms.
The periodic
table contains
118 elements and
arranges them
according to
their
characteristics
(atomic number).
A molecule is two
or more atoms
that are
chemically
bonded. Not all
molecules are
compounds but
all compounds
are molecules.
A compound is
made of atoms of
different
elements bonded
together. Two or
more elements
chemically bond
to make a
compound.

4. THE
PERIODIC
TABLE
Gives names and symbols for the
elements
18 groups (columns) and 7 periods
(rows)
They give the characteristics of
different elements
The ladder towards the right of the
periodic table separates the metals
from the non-metals
Atomic number, nucleon number and
relative atomic mass are also given
on the periodic table

5. ATOMIC NUMBER AND
NUCLEON NUMBER
ATOMIC NUMBER
It is the number of protons in an
atoms nucleus
NUCLEON NUMBER
Number of protons and neutrons.
Also called the mass number
In a neutral atom (no charge), the number of protons equal
the number of neutrons

6. ARRANGEMENT OF
PARTICLES
Protons and neutrons
are in the nucleus
Electrons orbit around
the nucleus
Protons have a positive
charge
Electrons have a
negative charge
Neutrons have no
charge
Electrons are present in
different levels known
as electron shells
First shell - 2 electrons
max
Second and third shell -
8 electrons max

7. ELECTRONIC
CONFIGURATION
Electrons are
added to
every shell
Electronic
configuration
is written like
2, 8, 8 (Argon)

8. VALENCY AND
VALENCE ELECTRONS
Valency is the amount of
electrons that is required to
make an atom stable.
Atoms can either give or
take electrons.
Valence electrons are the
number of electrons in the
outermost shell of an atom
Sodium (Atomic no. 11)
Valency - 1
Calcium (Atomic no. 20)
Valency - 2
Sodium (Atomic no. 11)
Valence Electrons - 1
Calcium (Atomic no. 20)
Valence Electrons - 2

9. NAMING
FORMULAE OF
CHEMICAL
COMPOUNDS
Sodium Chloride:
1 1
Na Cl
NaCl
Beryllium Chlroide:
2 1
Be Cl
BeCl₂
Potassium Hydroxide
1.
Magenisum Hydroxide
2.
Aluminium Oxide
3.
Boron Sulphate
4.
Calium Chloride
5.

10. BIBLIOGRAPHY
Gallagher, RoseMaria, and
Paul Ingram. “Atoms and
Elements.” Cambridge
IGCSE & O Level Complete
Chemistry, 4th ed., Oxford
University Press, 2021, pp.
14–19.
“Atomic Number Images –
Browse 265,286 Stock
Photos, Vectors, and
Video.” Adobe Stock,
https://stock.adobe.com/
au/search?
k=atomic+number.
Accessed 28 June 2024.
“Periodic Table of
Elements.” Periodic Table,
https://www.periodictable
.co.za/. Accessed 28 June
2024.

11. THANK YOU