Exam Focus

🎯 Exam Focus

Frequently Examined

The development of the periodic table is a favourite topic for 4-6 mark extended writing questions because it tests understanding of how science progresses. Examiners specifically want: a description of early attempts (Döbereiner/Newlands) and their limitations; Mendeleev's three key improvements (gaps, predictions, swaps); and the modern change to ordering by atomic number. Higher tier questions may ask why Mendeleev's predictions were accepted as evidence that his table was correct.

Edexcel 1CH0: Examined in Paper 1 (1CH0/1). Edexcel questions on this topic typically ask students to evaluate Newlands' and Mendeleev's contributions, explain why Mendeleev left gaps, and describe how the discovery of protons led to ordering by atomic number. "Evaluate" questions worth 4–6 marks are common. In Edexcel-style questions, the command word "Suggest" appears frequently — use your chemistry knowledge to apply to an unfamiliar context.