Electron Configuration Examples for First 20 Elements

⚛️ Quick Study Guide

• 🧪 Electron configuration describes the arrangement of electrons in an atom.
• 🔑 Electrons fill energy levels and sublevels in a specific order.
• 📈 The Aufbau principle states that electrons first fill the lowest energy levels.
• 📏 Hund's rule states that within a sublevel, electrons individually occupy each orbital before any orbital is doubly occupied, and all electrons in singly occupied orbitals have the same spin.
• 📐 The Pauli exclusion principle states that no two electrons in the same atom can have the same set of four quantum numbers.
• 🔢 The first 20 elements are: Hydrogen (H), Helium (He), Lithium (Li), Beryllium (Be), Boron (B), Carbon (C), Nitrogen (N), Oxygen (O), Fluorine (F), Neon (Ne), Sodium (Na), Magnesium (Mg), Aluminum (Al), Silicon (Si), Phosphorus (P), Sulfur (S), Chlorine (Cl), Argon (Ar), Potassium (K), and Calcium (Ca).
• ✏️ Electron configuration notation: $1s^22s^22p^63s^23p^64s^2...$

🧪 Practice Quiz

1. Which of the following is the correct electron configuration for Oxygen (O)?
   1. A) $1s^22s^22p^2$
   2. B) $1s^22s^22p^3$
   3. C) $1s^22s^22p^4$
   4. D) $1s^22s^22p^5$
2. What is the electron configuration of Sodium (Na)?
   1. A) $1s^22s^22p^63s^2$
   2. B) $1s^22s^22p^5$
   3. C) $1s^22s^22p^63s^1$
   4. D) $1s^22s^22p^63p^1$
3. Which element has the electron configuration $1s^22s^22p^6$?
   1. A) Oxygen
   2. B) Fluorine
   3. C) Neon
   4. D) Sodium
4. The electron configuration of Potassium (K) is:
   1. A) $1s^22s^22p^63s^23p^6$
   2. B) $1s^22s^22p^63s^23p^64s^2$
   3. C) $1s^22s^22p^63s^23p^64s^1$
   4. D) $1s^22s^22p^63s^23p^54s^2$
5. What is the electron configuration for Carbon (C)?
   1. A) $1s^22s^22p^1$
   2. B) $1s^22s^22p^2$
   3. C) $1s^22s^22p^3$
   4. D) $1s^22s^22p^4$
6. Which of the following represents the electron configuration of Magnesium (Mg)?
   1. A) $1s^22s^22p^63s^1$
   2. B) $1s^22s^22p^43s^2$
   3. C) $1s^22s^22p^63s^2$
   4. D) $1s^22s^22p^64s^2$
7. What is the electron configuration of Argon (Ar)?
   1. A) $1s^22s^22p^63s^23p^4$
   2. B) $1s^22s^22p^63s^23p^5$
   3. C) $1s^22s^22p^63s^23p^6$
   4. D) $1s^22s^22p^63s^23p^7$