Year 8 Atoms, Elements and Compounds Worksheet - Intermediate

Year 8 Atoms, Elements and Compounds worksheet for Year 8 (Key Stage 3 / Year 7-9 (Ages 11-14)). Intermediate 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 Compoundsintermediate

36 views

Atoms, Elements and Compounds

Year 8 Science • Ages 12–13 • Intermediate

Name:

Date:

Score:

Instructions: Work through each activity and use the information in the questions to explain your thinking. Write clearly in the answer spaces; include working or examples where requested.

Atoms, Elements and Compounds

Read each description carefully. Decide whether it describes an atom, an element or a compound. Give a short reason for each answer, using ideas about the kinds of atoms present.

1. A sample contains only oxygen atoms, all of the same type. What is it?

2. A particle contains two hydrogen atoms joined to one oxygen atom. What is it?

3. One particle of helium contains a single helium atom. Is this an atom, an element or a compound?

4. A substance contains carbon and oxygen atoms chemically joined in each particle. What is it?

Chemical Symbols and Formulae

Use correct chemical symbols, including capital letters where needed. For formula questions, use the small numbers to show how many atoms of each element are present; do not add a small number 1.

1. Write the chemical symbol for sodium.

2. Write the chemical symbol for iron.

3. How many oxygen atoms are in CO₂?

4. How many hydrogen atoms are in H₂O?

5. Write the formula for a compound containing one carbon atom and two oxygen atoms.

Reading the Periodic Table

Use your knowledge of the layout of the periodic table. A group is a vertical column and a period is a horizontal row. For each question, write the requested answer and give a brief explanation where asked.

1. Are elements in Group 1 arranged in a vertical group or a horizontal period?

2. Is Period 3 a row or a column in the periodic table?

3. In which broad region of the periodic table are most metals found: left and centre, or right-hand side?

4. Which broad region contains most non-metals: left and centre, or right-hand side?

Comparing Metals and Non-metals

Use the property bank to complete the statements. Each property is used once. Then answer the final question using a property from the bank.

Property bank: brittle when solid, conducts electricity, dull surface, malleable

1. Many metals can be hammered into shape because they are ___.

2. A typical solid non-metal may be ___ and break when struck.

3. Most metals are good conductors of electricity. Write one other property from the bank that is typical of metals.

4. Which listed property is more typical of a solid non-metal than a metal?

Dalton’s Model of the Atom

Dalton’s model was an early scientific model, so answer using what the model proposed rather than modern atomic structure. Explain your ideas in complete sentences where requested.

1. In Dalton’s model, what shape were atoms represented as?

2. Did Dalton describe atoms as solid, indivisible particles or as particles with a nucleus and electrons?

3. According to Dalton’s model, are atoms of one element the same as or different from atoms of another element?

4. State one way Dalton’s model differs from the modern model of the atom.

Apply Your Understanding

Read each statement and decide whether it is correct. If it is incorrect, write a corrected version. Use precise science vocabulary and chemical notation.

1. “A compound contains atoms of just one element.” Correct or incorrect? Explain.

2. “The formula H₂O represents two hydrogen atoms and one oxygen atom.” Correct or incorrect? Explain.

3. “Most metals are found on the right-hand side of the periodic table.” Correct or incorrect? Explain.

Answer Key

Activity 1: 1. Element: it contains only one type of atom. ; 2. Compound: it contains different types of atoms chemically joined. ; 3. Atom: it is one helium atom. ; 4. Compound: it contains carbon and oxygen atoms chemically joined.

Activity 2: 1. Na ; 2. Fe ; 3. 2 ; 4. 2 ; 5. CO₂

Activity 3: 1. A vertical group. ; 2. A horizontal row. ; 3. Left and centre. ; 4. Right-hand side.

Activity 4: 1. Malleable. ; 2. Brittle when solid. ; 3. Conducts electricity. ; 4. Dull surface.

Activity 5: 1. As solid spheres. ; 2. Solid, indivisible particles. ; 3. Different: atoms of different elements were considered different. ; 4. Dalton’s atoms were indivisible; the modern model includes smaller particles, including protons, neutrons and electrons.

Activity 6: 1. Incorrect. A compound contains atoms of at least two different elements chemically joined. ; 2. Correct. The small 2 applies to hydrogen; oxygen has no subscript, so there is one oxygen atom. ; 3. Incorrect. Most metals are found on the left-hand side and in the centre of the periodic table.