Chemistry Year 11 - Module 1 - Lesson 16
Electron Configuration: Subshell Notation
1. Key Ideas
MRI machines use superconducting magnets that only work near absolute zero. The technology relies on understanding how electrons fill energy levels in certain transition metals. Fireworks glow because electrons in metal salts jump to excited states then crash back down, releasing photons of specific colours — copper gives blue, strontium gives red, barium gives green. Every colour of light from every atom in the universe traces back to electron configuration. This lesson gives you the full quantum mechanical picture of how electrons are arranged in atoms — the foundation of everything from the periodic table trends to chemical bonding.
- The four quantum numbers (n, l, mₗ, mₛ) and what they describe
- Why subshells fill in a specific order (energy order)
2. Success Criteria
By the end, you should be able to:
- The four quantum numbers (n, l, mₗ, mₛ) and what they describe
- Subshell types: s (2e), p (6e), d (10e), f (14e)
- The Aufbau principle, Pauli exclusion principle, and Hund's rule
3. Key Terms
4. Activity: Build the Lesson Map
Use the lesson to complete the table. Keep answers brief but specific.
| Prompt | Your answer |
|---|---|
| Main concept | |
| Important example | |
| Common mistake to avoid | |
| How this links to the next lesson |
5. Short Answer Questions
1. 6. Write the full electron configuration for each element and identify: the number of valence electrons, and the group and period the element belongs to. (a) Silicon (Z=14), (b) Manganese (Z=25).
2. 7. Explain why chromium (Z=24) has the configuration [Ar]3d⁵4s¹ rather than the expected [Ar]3d⁴4s². In your answer, refer to orbital stability and electron repulsion.
6. Extend: Apply the Idea
A student gives a memorised answer about Electron Configuration: Subshell Notation but does not use evidence or reasoning.
Improve the answer by writing a stronger response that uses accurate terminology, a relevant example and a clear explanation.
7. Multiple Choice
1. What is the best first step when answering a question about Electron Configuration: Subshell Notation?
A. Identify the key concept being tested
B. Write every fact from memory
C. Ignore the command word
D. Skip examples and evidence
2. Which answer would show stronger understanding of Electron Configuration: Subshell Notation?
A. An answer with accurate terms and reasoning
B. A copied definition only
C. A single-word response
D. An answer with no example
3. What should you do if a question asks you to explain?
A. Link the idea to a reason or cause
B. List unrelated facts
C. Only draw a diagram
D. Write the shortest possible answer
8. Success Criteria Proof
Finish with evidence that you can do each success criterion.