Atomic & Ionic Radius Trends | Atomic Structure L4 | AS Chemistry (CIE 9701)

Lesson 4 of Atomic Structure for Cambridge International AS Level Chemistry (9701). How atomic and ionic radius change across a period and down a group, the "tug of war" that explains it, and isoelectronic species. ⏱️ CHAPTERS 0:00 Introduction 1:12 Measuring size 3:09 The tug of war 6:41 Across a period 10:43 Down a group 12:53 Ionic radius 18:31 Isoelectronic species 23:19 Recap 📝 PAST PAPER QUESTIONS 8:53 The graph shows the atomic and ionic radii of the Period 3 elements, sodium to chlorine. Explain the trend in the atomic radii. [2] (2025) 15:32 Explain why there is a large difference in the ionic radii of aluminium and phosphorus. [2] (2025) 17:14 The Group 2 elements form 2+ ions. State and explain the variation in ionic radius down the group. [2] (2025) 20:37 Arrange F⁻, Ne and Na⁺ in order of increasing radius, and explain your answer. [4] (2025) 22:05 Put Mg²⁺, Na⁺ and F⁻ in order of increasing radius. ▶ Watch the whole Atomic Structure chapter in order:    • Atomic Structure | AS Chemistry 9701 (CIE)...   📘 Full AS Chemistry 9701 course:    • AS Level Chemistry 9701 Full Course | CIE ...   🎓 The entire AS & A Level course is available on https://www.askpapers.com 📚 Practise on AskPapers • Topical past papers → https://www.askpapers.com/topics • Yearly papers + mark schemes → https://www.askpapers.com/papers • Revision notes → https://www.askpapers.com/notes • AI tutor → https://www.askpapers.com/tutor 🔔 Subscribe for full syllabus lessons, most repeated questions and solved past papers for Cambridge AS & A Level Chemistry. #ALevelChemistry #ASChemistry #9701 #CAIE #CIEChemistry #AtomicStructure #AtomicRadius #IonicRadius #PeriodicTrends #Chemistry AskPapers is not affiliated with or endorsed by Cambridge University Press & Assessment. Past-paper questions are © UCLES and used for educational commentary.