From Mendeleev to the Modern Table
Part of Development of Periodic Table — GCSE Chemistry
This key facts covers From Mendeleev to the Modern Table 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 6 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 6 of 13
Practice
20 questions
Recall
20 flashcards
🔄 From Mendeleev to the Modern Table
What changed?
- 1913 — Henry Moseley discovered elements should be arranged by atomic number (protons), not atomic weight
- This fixed the few elements Mendeleev had to swap around
- 1890s — Noble gases discovered and added as Group 0
Why atomic number works better: Atomic number = electrons = chemical properties!
Quick Check: Give two ways in which Mendeleev's periodic table was better than Newlands' table of octaves.
1. Mendeleev left gaps for undiscovered elements, whereas Newlands forced all known elements in without gaps. 2. Mendeleev predicted properties of the missing elements (confirmed when discovered), whereas Newlands made no predictions.