Ionisation Energy Trends Explained | Atomic Structure L8 | AS Chemistry (CIE 9701)

Lesson 8 of Atomic Structure for Cambridge International AS Level Chemistry (9701). Trends in first ionisation (ionization) energy across a period and down a group, comparing species, and reading successive ionisation energy data. ⏱️ CHAPTERS 0:00 Introduction 1:39 Across a period 9:41 Down a group 14:57 Comparing species 21:23 Reading successive IEs 31:40 Recap 📝 PAST PAPER QUESTIONS 8:00 Explain why the first ionisation energy of sulfur is less than the first ionisation energy of phosphorus. [2] (2025) 12:45 The graph shows first ionisation energy against proton number, with letters instead of symbols. Which statement is correct? (MCQ, 2023) 18:15 Why is the second ionisation energy of sodium larger than the second ionisation energy of magnesium? (MCQ, 2025) 19:52 Which process has the largest enthalpy change per mole: Al³⁺ → Al⁴⁺, P⁵⁺ → P⁶⁺, S⁶⁺ → S⁷⁺ or Si⁴⁺ → Si⁵⁺? (MCQ, 2024) 24:54 The successive ionisation energies of beryllium are 900, 1760, 14 800 and 21 000 kJ mol⁻¹. State and explain the general trend, and the significance of the large difference between the second and third. [2] (2025) 26:19 The first three ionisation energies of potassium are 418, 3070 and 4600 kJ mol⁻¹. Use these to explain why potassium is in Group 1. [2] (2022) 27:33 The diagram shows the log of the first thirteen ionisation energies of an element. Which statement is correct? (MCQ, 2025) 28:52 The graphs show the first eight ionisation energies of two elements in Period 3. What is the formula of the ionic compound they form? (MCQ, 2024) 30:21 The graph shows some of the ionisation energies of silicon. Complete it to show the third to sixth ionisation energies. [2] (2024) ▶ 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 #IonisationEnergy #IonizationEnergy #PeriodicTrends #Chemistry AskPapers is not affiliated with or endorsed by Cambridge University Press & Assessment. Past-paper questions are © UCLES and used for educational commentary.