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The Periodic Table: Chemical Nomenclature

In this worksheet, students will learn how to name chemical compounds according to IUPAC (International Union of Pure and Applied Chemistry) rules.

'The Periodic Table: Chemical Nomenclature' worksheet

Key stage:  KS 3

Curriculum topic:   Working Scientifically

Curriculum subtopic:   Measurement

Difficulty level:  

Worksheet Overview

QUESTION 1 of 10

This is the Periodic Table of the elements (click on it to see a larger version):

 

 

Chemical symbols are used to show an element instead of using the element name. For example, oxygen is shown as O and calcium is shown as Ca. Some elements have one letter symbols, whereas some others have two letter symbols. It is imperative that the first letter of each symbol is a capital letter to avoid confusion. Check the following: Co is the symbol for cobalt. Writing it as CO would make it stand for carbon monoxide, so there would be confusion in interpreting the symbol. 

 

Chemical formulae

Let's start with some definitions:

An atom is a stable chemical entity, a whole. An atom cannot be broken down by any chemical process. It is the smallest entity of an element that can be found in nature. Some elements can stand as atoms alone, whereas some others need to form molecules – two atoms together. A molecule refers to two or more atoms that have chemically bonded to make a stable entity. For example, sodium (Na) is found in nature as one atom. Oxygen, on the other hand, cannot stand alone as one atom (O). The air we breathe in contains molecules of oxygen, i.e. two oxygen atoms bonded together. We refer to a molecule of oxygen as O2, where O shows that the element is oxygen and the subscript 2 shows we are referring to two oxygen atoms, which we have come to recognize as a molecule of oxygen. Note that it would be wrong to write O2. The number must always be at the bottom after the element that it refers to. 

 

Elements of the periodic table react and form compounds. We use chemical formulae to refer to those compounds. Formulae is the plural of the word 'formula'. There are rules to follow when naming those compounds. The formula must show the atoms that the chemical compound contains. For example, carbon dioxide contains one carbon atom and two oxygen atoms. We write this as CO2. This clearly reflects the one carbon atom and the two oxygen atoms. As for element molecules above, CO2 would be wrong.

Chemical formulae look more complicated for complex compounds. Potassium nitrate's formula is KNO3. Do not worry, but break it down slowly. K is the symbol for potassium (you may have to search the periodic table until you learn the main symbols). There is no number below it, so there is only one potassium atom in potassium nitrate. N is the symbol for nitrogen and no numbers below means there is only one nitrogen atom. Finally, O is the symbol for oxygen. Number 3 is below it, so three oxygen atoms are found in potassium nitrate. 

Chemical formulae can get a bit harder but no harder than the following example. Your maths knowledge would be beneficial here. Aluminium sulfate has a more complex formula, Al2(SO4)3. Aluminium sulfate contains two aluminium atoms and then the group SO4 three times. Anything inside the brackets must be multiplied by number 3, because this is the subscript that refers to the whole bracket. Here we go: 3 times S gives 3 sulfur atoms, and 3 times O4 gives 3 × 4 = 12 oxygen atoms.

Now we need to look at the rules for naming the compounds from looking at the formula:

 

Rule 1: Naming simple compounds

Compounds that are formed by two elements, a metal and a non-metal, are named by the name of the metal (the first symbol of the formula) followed by the name of the non-metal with the ending -ide. Let's look at some examples. NaCl is made of sodium (Na) and chlorine (Cl). Its name would be the name of the metal (sodium) followed by the name of the non-metal (chlorine) with -ide at the end; sodium chloride. 

Have a go at naming the following compound, FeS, Fe is iron and S is sulfur.

Did you answer iron sulfide? Correct!

 

Rule 2: Naming further compounds

Some compounds may contain a metal, a non-metal and oxygen, like Al2(SO4)3 above. In this case, we follow rule 1, but change the ending to -ate. Aluminium is the metal, sulfur is the non-metal, so it becomes aluminium sulfate. Another example is Al(BrO3)3. Its name would be aluminium bromate.

What is the correct formula for carbon dioxide?

CO2

Co2

CO2

This is the formula for water: H2O. How many types of atoms does water contain?

1

2

3

Is this statement true or false?

 

This formula refers to a hydrogen atom: H2.

true

false

What is the formula for cobalt chloride if it is made of one cobalt atom and two chloride atoms?

COCL2

CoCl2

Co2

What is the correct formula for magnesium oxide, if it is made of one magnesium atom and one oxygen atom?

What is the name of this compound, ZnS?

zinc sulfate

zinc sulfide

zinc oxide

What is the name of this compound, NiI2?

nickel iodide

nickel iodine

nickel iodate

What is the name of this compound, CuSO4?

copper sulfide

copper sulfur oxide

copper sulfate

What is the name of this compound, NaNO3?

sodium nitrate

sodium nitride

sodium nitrogen peroxide

What is the name of this compound, NiSO4?

nickel sulfate

nickel sulfide

nickel oxygen sulfate

  • Question 1

What is the correct formula for carbon dioxide?

CORRECT ANSWER
CO2
EDDIE SAYS
The correct formula for carbon dioxide is CO2.
  • Question 2

This is the formula for water: H2O. How many types of atoms does water contain?

CORRECT ANSWER
2
EDDIE SAYS
Water contains two different types of atoms, hydrogen (H) and oxygen (O).
  • Question 3

Is this statement true or false?

 

This formula refers to a hydrogen atom: H2.

CORRECT ANSWER
false
EDDIE SAYS
The statement is false; the formula refers to a molecule of hydrogen, as the subscript shows there are two hydrogen atoms.
  • Question 4

What is the formula for cobalt chloride if it is made of one cobalt atom and two chloride atoms?

CORRECT ANSWER
CoCl2
EDDIE SAYS
The correct formula for cobalt chloride is CoCl2.
  • Question 5

What is the correct formula for magnesium oxide, if it is made of one magnesium atom and one oxygen atom?

CORRECT ANSWER
MgO
EDDIE SAYS
The correct formula for magnesium oxide is MgO. Mg for magnesium and O for oxygen.
  • Question 6

What is the name of this compound, ZnS?

CORRECT ANSWER
zinc sulfide
EDDIE SAYS
The compound referred to by this formula is zinc sulfide, Zn for zinc and S for sulfur.
  • Question 7

What is the name of this compound, NiI2?

CORRECT ANSWER
nickel iodide
EDDIE SAYS
The compound referred to by this formula is nickel iodide, Ni for nickel and I for iodine.
  • Question 8

What is the name of this compound, CuSO4?

CORRECT ANSWER
copper sulfate
EDDIE SAYS
The compound referred to by this formula is copper sulfate, Cu for copper and the sulfur and oxygen together (combined as one atom of sulfur with 4 atoms of oxygen) make it a sulfate.
  • Question 9

What is the name of this compound, NaNO3?

CORRECT ANSWER
sodium nitrate
EDDIE SAYS
The compound referred to by this formula is sodium nitrate, Na for sodium and the nitrogen and oxygen together make it a nitrate.
  • Question 10

What is the name of this compound, NiSO4?

CORRECT ANSWER
nickel sulfate
EDDIE SAYS
The compound referred to by this formula is nickel sulfate, Ni for nickel and the sulfur and oxygen together make it a sulfate.
---- OR ----

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