Year 8 Science · Unit 2 · Lesson 20

Atoms and Elements, Unit Review

Challenge Worksheet

Name

Date

Class

Learning Goals

Use periodic table patterns to make and justify predictions about an unknown element.
Construct multi-step reasoning chains linking atomic structure, position, properties and uses.
Evaluate how new scientific evidence changes our understanding.

Go Deeper

What if…?

Scenario

In 2026, a team of physicists at a particle accelerator in Darmstadt, Germany announce the confirmed discovery of element 119. This places it directly below francium (Fr, atomic number 87) in Group 1 of the periodic table, making it the first element in Period 8. Scientists have so far produced only a handful of atoms, each lasting milliseconds before decaying, so no physical properties have been measured directly.

Using the patterns and principles from Unit 2, predict what element 119 would be like if a stable form could ever be produced.

Using what you know from this unit, predict and explain: (i) whether element 119 would be a metal, non-metal, or metalloid; (ii) how its reactivity with water would compare to other Group 1 elements such as lithium and francium; (iii) whether you would expect it to be stable or radioactive; and (iv) one potential use if a safe, stable form could be synthesised. Justify every prediction using patterns from the periodic table or atomic structure.

Challenge 4 marks

Show What You Know

1. Aluminium (atomic number 13, Group 13, Period 3) is used in aircraft bodies, while iron (atomic number 26, Group 8, Period 4) is used in bridge frames. Use your knowledge of protons and atomic number, periodic table position, and physical properties to explain why each element is chosen for its specific use, and why you could not simply swap them around.

Challenge 4 marks

2. The atomic model changed significantly from Dalton (1803) to Bohr (1913). Explain why each new model replaced the previous one and what this tells us about how science works as a self-correcting process.

Challenge 3 marks

Wrap Up

What was the most surprising connection you made between ideas in Unit 2?