Grade 10 CBC Chemistry | s and p orbitals: why does energy level 2 hold 8 electrons?

Does an electron really travel round the nucleus on a circle? And why does energy level 2 hold exactly 8 electrons? In this Grade 10 CBC Chemistry lesson you will see why scientists replaced Bohr's orbits with orbitals, learn the shapes of s and p orbitals, meet sublevels, orbital boxes and the four quantum numbers, and use spin and the Pauli principle to explain why level 2 holds 2 + 6 = 8. A FREE REVISION PAPER FOR THIS LESSON Paper 1: Core concepts Download them here: https://drive.google.com/file/d/1OtOl... The marking schemes will be in the description of Video 4, so try the paper on your own first. MARKING SCHEMES FOR VIDEO 2 Did you try the revision paper from Video 2 (Isotopes and relative atomic mass)? Mark your work here: https://drive.google.com/file/d/17iPm... IN THIS VIDEO 0:00 Hook and title 0:29 In this video 1:11 Bohr's evidence: a line spectrum 1:52 Bohr's orbit 2:26 Two problems with Bohr's model 2:53 Electrons behave like waves 3:28 Why we cannot trace a path 4:06 Schrödinger's idea 4:45 Building a probability cloud 5:15 From cloud to orbital 5:39 Orbit or orbital? 6:13 Types of orbital: s and p 6:48 s orbitals are spheres 7:16 p orbitals are dumbbells 7:49 Your turn: name this orbital 8:21 From atom to orbital 8:56 Sublevels in each energy level 9:31 Sublevels have different energies 10:07 The electron's address 10:38 The first two numbers: n and ℓ 11:28 The last two numbers 12:01 Your turn: is there a 1p orbital? 12:39 What is spin? 13:20 The Pauli principle 13:44 Why level 2 holds 8 14:31 Your turn: energy level 3 15:19 Watch out for these mistakes 16:11 What to remember 16:59 Challenge and next video YOUR CHALLENGE For the first 20 elements, how many orbitals are there in energy levels 1, 2 and 3 together, and how many electrons can they hold altogether? Write your answer in the comments. PREVIOUS VIDEO Video 2: Isotopes and relative atomic mass :    • Grade 10 CBC Chemistry | isotopes and rela...   NEXT VIDEO Video 4: Electron configurations for elements 1 to 20. We fill these boxes one electron at a time. Coming soon. THE FULL PLAYLIST Playlist 1: The Atom :    • Grade 10 CBC Chemistry | isotopes and rela...   ABOUT SP-SciLearn SP-SciLearn makes paced, interactive science lessons for Kenyan learners following the CBC. Every video stops so that you can try a question yourself before the answer appears. Subscribe and turn on notifications so that you do not miss the next lesson. Grade 10 CBC Chemistry · 1.2 The Atom #Grade10Chemistry #CBCKenya #Chemistry