How do I revise E2E stub topic for WJEC GCSE?

Use Mendeleev's predicted element (ekasilicon) as a concrete example to illustrate predictive power.

What exam tips are there for E2E stub topic? (2)

When comparing early and modern tables, clearly state the ordering principle (atomic mass vs atomic number) and its impact.

What exam tips are there for E2E stub topic? (3)

Ensure to reference specific examples of anomalies (e.g., tellurium and iodine) that were resolved.

What mistakes should I avoid in E2E stub topic?

Confusing Mendeleev with earlier scientists or attributing the modern table entirely to him.

What are common errors in E2E stub topic exams? (2)

Misunderstanding that elements are arranged by atomic mass rather than atomic number in the modern table.

E2E stub topic

WJEC

GCSE

This subtopic explores the historical development of the periodic table, from early attempts by scientists like Döbereiner and Newlands to the modern arrangement by Mendeleev and its subsequent refinements. It examines how arranging elements by atomic number rather than atomic mass resolved inconsistencies and allowed predictions of undiscovered elements. Understanding this progression highlights the nature of scientific discovery and the predictive power of the periodic table in chemistry.

Objectives

Exam Tips

Pitfalls

Key Terms

Mark Points

What You Need to Demonstrate

Key skills and knowledge for this topic

Award credit for correctly identifying key scientists and their contributions (e.g., Döbereiner's triads, Newlands' octaves).
Credit explanations that link Mendeleev's arrangement to the prediction of missing elements (e.g., gallium, germanium).
Award marks for explaining how the use of atomic number resolves anomalies observed in early tables.
Look for accurate use of terminology such as group, period, and atomic number.

Marking Points

Key points examiners look for in your answers

Award credit for correctly identifying key scientists and their contributions (e.g., Döbereiner's triads, Newlands' octaves).
Credit explanations that link Mendeleev's arrangement to the prediction of missing elements (e.g., gallium, germanium).
Award marks for explaining how the use of atomic number resolves anomalies observed in early tables.
Look for accurate use of terminology such as group, period, and atomic number.

Examiner Tips

Expert advice for maximising your marks

💡Use Mendeleev's predicted element (ekasilicon) as a concrete example to illustrate predictive power.
💡When comparing early and modern tables, clearly state the ordering principle (atomic mass vs atomic number) and its impact.
💡Ensure to reference specific examples of anomalies (e.g., tellurium and iodine) that were resolved.

Common Mistakes

Pitfalls to avoid in your exam answers

Confusing Mendeleev with earlier scientists or attributing the modern table entirely to him.
Misunderstanding that elements are arranged by atomic mass rather than atomic number in the modern table.
Failing to recognise that Mendeleev's predictions were based on pattern gaps.

Study Guide Available

Comprehensive revision notes & examples

Read Study Guide

Key Terminology

Essential terms to know

Early classification attempts

Mendeleev's predictions

Atomic number vs mass

Modern periodic law

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E2E stub topic

What You Need to Demonstrate

Marking Points

Examiner Tips

Common Mistakes

Study Guide Available

Key Terminology

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