Year 8 Science · Unit 2 · Lesson 12

Groups and Periods

Challenge Worksheet

Name

Date

Class

Learning Goals

Clearly distinguish groups from periods using scientific language
Identify an unknown element's group using evidence about its chemical behaviour
Evaluate and critique scientific reasoning about element classification

Go Deeper

Explain it to a student who keeps getting confused

A classmate keeps mixing up groups and periods. Use the sentence starters below to write a clear, precise explanation. You can use examples from the lesson. Aim for accuracy, avoid vague phrases like "it goes across" without saying what that means.

"A group in the periodic table is..."

"A period is different because..."

"The useful thing about groups is..."

"One thing that trips people up is..."

Show What You Know

1. An unknown element reacts vigorously with water, produces a flammable gas, and turns litmus solution blue. Predict which group this element most likely belongs to. Justify your answer using at least two pieces of evidence from this lesson.

Challenge 4 marks

2. Consider this claim: "Because sodium (Na) and chlorine (Cl) are both in Period 3, they must have similar chemical properties." Explain why this reasoning is flawed, and describe what Period 3 actually tells us about sodium and chlorine.

Challenge 3 marks

Wrap Up

In one sentence, what was the main idea of this lesson?