Atoms, Elements and Compounds Worksheet - KS3 - Beginner

Atoms, Elements and Compounds worksheet for KS3 (Key Stage 3 / Year 7-9 (Ages 11-14)). Beginner level science practice, aligned to the UK National Curriculum. Print-ready with answer key included.

Science•Key Stage 3 / Year 7-9 (Ages 11-14)•Atoms, Elements and Compoundsbeginner

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Atoms, Elements and Compounds

Key Stage 3 · Years 7–9 · Beginner

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Instructions: Work through the activities in order. Use the examples and data provided to help you, and write each answer in its box. Chemical symbols use one or two letters: the first letter is always a capital, and any second letter is lower case.

Key ideas: atoms, elements and compounds

Choose the best answer for each question. An element contains one type of atom; a compound contains different elements chemically joined. A mixture contains substances together without them being chemically joined.

1. What is the smallest particle that makes up an element?

2. Which statement describes an element?

3. In a compound, the different elements are:

4. Which is a mixture?

Elements or compounds?

Classify each substance using its formula. A formula containing only one element symbol represents an element. A formula containing symbols for more than one element represents a compound. Write your classification in each box.

1. Helium, He: element or compound?

2. Water, H₂O: element or compound?

3. Oxygen, O₂: element or compound?

4. Carbon dioxide, CO₂: element or compound?

Chemical symbol check

Use the element names and symbols to complete each answer. Remember that symbols may have one or two letters, and the second letter—if there is one—is lower case.

Reference: hydrogen H; carbon C; oxygen O; sodium Na; chlorine Cl; iron Fe.

1. Write the symbol for oxygen.

2. Name the element with the symbol Na.

3. Write the symbol for iron.

4. Name the element with the symbol Cl.

Reading the periodic table

Use the simplified periodic-table extract below. A group is a vertical column; a period is a horizontal row. Find each element in the extract and answer the questions.

Group 1

Group 17

Group 18

Period 1

Hydrogen (H)

—

Helium (He)

Period 2

Lithium (Li)

Fluorine (F)

Neon (Ne)

1. Which element is in Group 18 and Period 2?

2. What is the symbol for lithium?

3. Which group contains fluorine in this extract?

Element, compound or mixture?

Read each description carefully. Decide whether it describes an element, a compound or a mixture. For a mixture, the substances are together but are not chemically joined to each other.

1. A sample containing only copper atoms.

2. Water particles, each made from hydrogen and oxygen atoms chemically joined.

3. Sand and salt mixed together, with no chemical joining between them.

4. Carbon dioxide particles, each made from carbon and oxygen atoms chemically joined.

Explain your thinking

Use the key terms in your explanation: atom, element, compound and mixture. Give a clear distinction between a compound and a mixture. The sentence starter is there to help you; complete it in your own words.

An element is made from ___. A compound contains different elements that are ___. In a mixture, the substances are ___. [3 marks]

Answer Key

Activity 1: atom ; One type of atom only ; chemically joined ; Air

Activity 2: element ; compound ; element ; compound

Activity 3: O ; sodium ; Fe ; chlorine

Activity 4: Neon ; Li ; Group 17

Activity 5: element ; compound ; mixture ; compound

Activity 6: Atoms ; chemically joined ; together but not chemically joined to each other (accept equivalent scientifically accurate wording)