Mendeleev's Genius (1869)
Part of Development of Periodic Table — GCSE Chemistry
This key facts covers Mendeleev's Genius (1869) within Development of Periodic Table for GCSE Chemistry. Revise Development of Periodic Table in Atomic Structure for GCSE Chemistry with 20 exam-style questions and 20 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 5 of 13 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 5 of 13
Practice
20 questions
Recall
20 flashcards
💡 Mendeleev's Genius (1869)
What made Mendeleev different? He was willing to break the rules when the evidence demanded it.
His key innovations:
- Left GAPS for undiscovered elements
- Predicted properties of missing elements with remarkable accuracy
- Swapped the order of some elements when their properties didn't fit (e.g., tellurium and iodine)
His predictions came true:
Mendeleev predicted "eka-aluminium": atomic weight ≈ 68, density ≈ 5.9 g/cm³, low melting point
Gallium discovered (1875): atomic weight = 69.7 ✓, density = 5.91 g/cm³ ✓, melts at 30°C ✓
Germanium (1886) matched his "eka-silicon" prediction
Scandium (1879) matched his "eka-boron" prediction
This proved his table revealed real patterns in nature!