Chemical Symbols
and Formulae
Understanding the Language of Chemistry
30
Zn
Zinc
12
Mg
esium
n
g
a
M
₂
l
C
Mg
What do they
mean?
Think of where you might have seen
these symbols outside of the classroom.
H₂O
3+
Fe
C₄H₁₀
Today, you will...
1
2
3
Represent elements
using chemical symbols.
Understand the basics of
IUPAC nomenclature in
naming compounds.
Use chemical formulae
to represent compounds.
Did You Know?
Swedish scientist Jöns Jakob Berzelius introduced the
modern system of chemical symbols. He represented the
elements using one or two letters from their latin names.
Chemical
Symbols
Each symbol is made up
of one or two letters.
Na
These are shorthand ways to
represent elements in chemistry.
Recall that an element cannot be
broken down into simpler
substances.
Sodium
Always
capitalise the
first letter!
Importance
of Chemical
Symbols
They provide standardised ways of
representing elements, making
communicating information about
elements and compounds easier.
They offer a concise and simple
way to represent elements in
chemical equations, eliminating the
need to spell each element's name.
Common
Chemical
Symbols
H
Hydrogen
O
Oxygen
C
Carbon
Derived from the Greek ‘hydro’ and
‘genes’, which means water forming
Most abundant element in the universe
Name comes from the Greek ‘oxy’ and
‘genes’, which means acid forming
Essential for life
Derived from the Latin ‘carbo’, meaning
charcoal
Found in all known life forms
Common
Chemical
Symbols
N
Nitrogen
Na
Sodium
Cl
Chlorine
Comes from the Greek ‘nitron’ and
‘genes’, meaning nitre forming
Constitutes about 78% of Earth's
atmosphere
Derived from the Latin ‘natrium’
Soft metal that easily tarnishes when
exposed to air
Name derived from the Greek ‘chloros’,
which means greenish yellow
Widely used in disinfectants and
cleaning products
Symbol Scrabble
How many elements can you recognise from the chemical symbols below?
Name as many as you can with the help of your peer.
Au
Ni
Mg
I
P
Ag
K
Ca
Hg
Al
Zn
C
ANSWER KEY
Symbol Scrabble
Elements are often named based on their characteristics, the substances they were
extracted from, how they were found, mythological beings, locations or notable individuals.
Au
Ni
Mg
I
P
Ag
Gold
Nickel
Magnesium
Iodine
Phosphorus
Silver
K
Ca
Hg
Al
Zn
C
Potassium
Calcium
Mercury
Aluminium
Zinc
Carbon
The Periodic
Table of
Elements
There are 118 chemical
elements listed in the
periodic table in a
specific order.
Rules on how to name
new elements in the
periodic table are set up
by the International
Union of Pure and
Applied Chemistry
(IUPAC).
1
2
H
He
3
4
5
6
7
8
9
10
Li
Be
B
C
N
O
F
Ne
11
12
13
14
15
16
17
18
Na
Mg
Al
Si
P
S
Cl
Ar
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
K
Ca
Sc
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
Ga
Ge
As
Se
Br
Kr
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
Rb
Sr
Y
Zr
Nb
Mo
Tc
Ru
Rh
Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
55
56
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
Hf
Ta
W
Re
Os
Ir
Pt
Au
Hg
Ti
Pb
Bi
Po
At
Rn
Cs
Ba
87
88
Fr
Ra
57-71
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
89-103
Rf
Db
Sg
Bh
Hs
Mt
Ds
Rg
Cn
Nh
Fl
Mc
Lv
Ts
Og
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
La
Ce
Pr
Nd
Pm
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
Ac
Th
Pa
U
Np
Pu
Am
Cm
Bk
Cf
Es
Fm
Md
No
Lr
The Role of
IUPAC
IUPAC is responsible for
establishing unambiguous and
consistent naming systems (also
known as nomenclature) and
terminology.
It has a system for naming chemical
compounds that provides a standard
language for scientists worldwide.
35
2
He
Heliu
m
?
----------
Naming
Compounds
The chemical formula for
carbon dioxide is CO₂.
A compound is a substance
containing two or more elements
that are chemically bonded.
A chemical formula is an
expression showing the elements in
a compound and their relative
proportions. It contains a
combination of chemical symbols
and numbers.
What does
the formula
CO₂ mean?
Naming Compounds
Carbon dioxide is a compound of carbon and oxygen.
Shown below is the
molecular model of
carbon dioxide.
one carbon
atom
CO₂
two oxygen
atoms because
of the
subscript ‘2’
O C O
Naming Ionic Compounds
An ionic compound is composed of a metal and non-metal. Some of the basic rules
when naming ionic compounds include:
1
2
3
A metal will always come
first in a chemical
formula, followed by a
non-metal.
An ionic compound with
two elements will have a
name that ends with -ide.
A compound with three
elements, including
oxygen, will have a name
that ends with -ate
or -ite.
Ex: sodium chloride
(NaCl)
Ex: copper sulfide
(CuS)
Ex: sodium sulphate
(NaSO₄)
Naming Covalent Compounds
A covalent compound has two or more non-metals. Some of the general rules
when naming covalent compounds are:
1
2
3
The non-metal furthest
to the left on the periodic
table comes first.
A covalent compound
with two elements will
have a name that ends
with -ide.
Use the prefixes (mono-,
di-, tri-, tetra-) to indicate
the number of that
element in the molecule.
Ex: carbon dioxide
(CO₂)
Ex: sulfur dioxide
(SO₂)
Ex: carbon tetrachloride
(CCl₄)
Naming Covalent Compounds
Remember that many covalent compounds have common names that
are widely accepted.
water
ammonia
methane
one
nitrogen
atom
two
hydrogen
atoms
H₂O
one
carbon
atom
NH₃
one
oxygen
atom
three
hydrogen
atoms
CH₄
four
hydrogen
atoms
Chemistry Name Game
Identify the correct chemical formulae for the following compounds.
potassium
bromide
lithium iodide
carbon
monoxide
sulfuric acid
potassium
nitrate
ANSWER KEY
Chemistry Name Game
Identify the correct chemical formulae for the following compounds.
potassium
bromide
KBr
lithium iodide
carbon
monoxide
sulfuric acid
potassium
nitrate
LiI
CO
H₂SO₄
KNO₃
Review
Chemical Symbols
These are shorthand
ways to represent
elements in chemistry.
Each symbol is made up
of one or two letters,
with the first letter
always capitalised.
IUPAC Nomenclature
IUPAC is responsible for
setting up a system of
naming elements and
compounds, providing a
standard language for
scientists worldwide.
Naming Compounds
Compounds are
represented by chemical
formulae, which use
symbols and subscripts.
IUPAC sets rules for
naming compounds
correctly.
Chemical
Formulae
Hunt
Identify and record the chemical
formulae, common names, and
corresponding IUPAC names for
five (5) common compounds found
at home.
H₂O
?
Na
Cl