"Electronic Configuration of Elements – Class 11 (Ch. 3)"

Electronic Configuration of Elements – Class 11 (Chapter 3)

This post explains the basic concept of electronic configuration using visual charts, simple rules, examples, and an MCQ quiz for NEET/CBSE students.

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📊 Electronic Configuration Chart

Shell	Subshell	Maximum Electrons	Electronic Configuration
K (n = 1)	1s	2	1s ⟶
L (n = 2)	2s, 2p	8	2s ⟶ 2p ⟶
M (n = 3)	3s, 3p, 3d	18	3s ⟶ 3p ⟶ 4s ⟶ 3d ⟶
N (n = 4)	4s, 4p, 4d, 4f	32	4p ⟶ 5s ⟶ 4d ⟶ 5p ⟶ 6s ⟶ 4f ⟶ 5d ⟶ 6p ⟶ 7s ⟶

🧠 Aufbau Principle (Filling Order)

1s
↓
2s → 2p
↓      ↓
3s → 3p → 4s
↓      ↓     ↓
3d → 4p → 5s
↓      ↓     ↓
4d → 5p → 6s
↓      ↓     ↓
4f → 5d → 6p → 7s

📗 Examples of Electronic Configurations

• Hydrogen (Z = 1) → 1s¹
• Carbon (Z = 6) → 1s² 2s² 2p²
• Oxygen (Z = 8) → 1s² 2s² 2p⁴
• Sodium (Z = 11) → 1s² 2s² 2p⁶ 3s¹
• Chlorine (Z = 17) → 1s² 2s² 2p⁶ 3s² 3p⁵

📝 Interactive MCQ Quiz – Electronic Configuration

1. What is the electronic configuration of Nitrogen (Z = 7)?
   • A. 1s² 2s² 2p²
   • B. 1s² 2s² 2p³
   • C. 1s² 2s² 2p⁴
   • D. 1s² 2s¹ 2p⁴
   Answer: B. 1s² 2s² 2p³ – Nitrogen has 7 electrons.
2. Which orbital is filled after 3p?
   • A. 4p
   • B. 3d
   • C. 4s
   • D. 5s
   Answer: C. 4s – According to the Aufbau principle.
3. Maximum electrons in 3p subshell is:
   • A. 6
   • B. 10
   • C. 14
   • D. 2
   Answer: A. 6 – Each p subshell holds 6 electrons.
4. Which of the following is a d-block element?
   • A. Na
   • B. Cl
   • C. Fe
   • D. He
   Answer: C. Fe – Transition metals belong to the d-block.

📘 Related Post:

IUPAC Rules and Nomenclature – Full Guide

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