G8 Chemistry
1.4 Chemical names
and Formulas
Learning Objectives
ZK Curriculum
•Identify the meanings
of chemical symbols理解
化学符号的意义
•Use the symbols of
elements and write
down the formulae of
some substances利用元素
符号写出一些物质的化学式
English Curriculum
•State the formulas of
the elements and
compounds named in
the subject content
1.4.2 Naming compounds
Types of compounds
Type1: one metal + one non-metal
Type2: one non-metal + one non-metal
Type3: one metal + two or more non-metals
1.4.2 Naming compounds
1.4.2 Naming compounds
Type1: one metal + one non-metal
 Writing
Formulas from Names
• 1st word = metal name
• 2nd word = non-mental name with
“ide” ending.
Eg. NaCl ➔ sodium chloride
NaBr ➔ sodium bromide
NaF ➔ sodium fluoride
1.4.2 Naming compounds
Type2: one non-metal + one non-metal
 Prefixes
are used to show how many atoms are present in
each chemical formula.



Mono (or no prefix) – 1
Di – 2
Tri – 3
CO2
•No mono prefix is
used on first element
Carbon Dioxide
•Di means 2 oxygens!!
1.4.2 Naming compounds
Type2: one non-metal + one non-metal



Mono (or no prefix) – 1
Di – 2
Tri – 3
CO ➔ carbon monoxide
PCl3 ➔ phosphorus trichloride
SiO2 ➔ silicon dioxide
N2O ➔ dinitrogen monoxide
1.4.2 Naming compounds
Type2: one non-metal + one non-metal
 Writing
Names from Formulas
silicon dioxide ➔ SiO2
sulfur trioxide ➔ SO3
1.4.2 Naming compounds
Type3: one metal + two or more non-metals
 Writing
Formulas from Names
• 1st word = metal name
• 2nd word = common polyatomic ions name
Symbol polyatomic ions Name
OH
hydroxide
SO4
sulphate/sulfate
CO3
NO3
PO4
carbonate
nitrate
Phosphate
E.g., Al2(SO4)3 ➔ aluminum sulphate
CaCO3 ➔ calcium carbonate
NaOH ➔ sodium hydroxide
Zn(NO3)2 ➔ zinc nitrate
SUMMARY