KONFIGURASI ELEKTRON MEKANIKA KUANTUM - MATERI KIMIA KELAS 10 | Edcent.id

Summary

In this educational video, Kak Tiara from kimia.sc.id explores the quantum mechanics of electron configuration. She explains the three principles governing electron arrangement: Aufbau's rule, Pauli's exclusion principle, and Hund's rule. The video uses the example of phosphorus (atomic number 15) to demonstrate how to fill electron shells and subshells step by step. It also discusses the concept of orbital stability and how electrons prefer to fill orbitals to achieve a stable configuration, using chromium (atomic number 24) and copper (atomic number 29) as examples. The video aims to make complex quantum mechanics concepts accessible and engaging.

Takeaways

• 📚 The video discusses electron configuration based on quantum mechanics, which is more advanced than the Bohr model.
• ⚛️ There are three main principles for quantum electron configuration: Aufbau Principle, Pauli Exclusion Principle, and Hund's Rule.
• 🔋 The Aufbau Principle states that electrons fill orbitals starting from the lowest energy level to the highest.
• 🔢 Energy levels and sublevels follow a specific order, such as 1s, 2s, 2p, 3s, 3p, and so on.
• 🔄 The Pauli Exclusion Principle explains that no two electrons in an atom can have the same set of quantum numbers, and each orbital can hold a maximum of two electrons with opposite spins.
• 🚀 Hund's Rule states that electrons fill degenerate orbitals (like p, d, f sublevels) singly with parallel spins before pairing up.
• ⚖️ Stability of orbitals is influenced by whether they are fully filled or half-filled, which affects electron promotion in cases like Chromium and Copper.
• 🧮 Example configurations for atoms like Phosphorus (P-15) and Iron (Fe-26) are demonstrated, showing how to apply the rules.
• 🔄 For transition metals like Chromium and Copper, electrons from the 4s orbital can be promoted to stabilize the 3d sublevel.
• 🔬 Understanding these principles helps in predicting the electron arrangement and stability of atoms in quantum mechanics.

Q & A

What is the difference between Bohr's electron configuration and the quantum mechanical electron configuration?

Bohr's electron configuration is based on electron shells or energy levels, while quantum mechanical electron configuration is more advanced, organizing electrons into sub-shells such as s, p, d, and f based on their energy.

What is the Aufbau principle in electron configuration?

The Aufbau principle states that electrons fill orbitals starting from the lowest energy level and move to higher energy levels sequentially.

How are sub-shells labeled in quantum mechanical electron configurations?

Sub-shells are labeled as s, p, d, and f, with s having 1 orbital, p having 3 orbitals, d having 5 orbitals, and f having 7 orbitals. Each orbital can hold up to two electrons.

What are the three key rules for determining electron configurations?

The three key rules are the Aufbau principle, Pauli’s exclusion principle (no two electrons can have the same quantum numbers in the same orbital), and Hund's rule (electrons fill orbitals singly with parallel spins before pairing up).

How is the stability of an orbital determined in quantum mechanical electron configurations?

An orbital is stable if it is either fully filled with electrons or half-filled with electrons. A fully or half-filled orbital provides additional stability to an atom.

What is an example of electron configuration for phosphorus (P) with atomic number 15?

The electron configuration for phosphorus is 1s² 2s² 2p⁶ 3s² 3p³, with the total electron count being 15.

Why is chromium (Cr) an exception in electron configuration?

Chromium (Cr) with atomic number 24 is an exception because one electron from the 4s orbital is promoted to the 3d orbital to achieve a more stable half-filled d-sub-shell configuration, resulting in 4s¹ 3d⁵ instead of the expected 4s² 3d⁴.

How is copper (Cu) an exception in electron configuration?

Copper (Cu) with atomic number 29 has an electron configuration of 4s¹ 3d¹⁰ instead of the expected 4s² 3d⁹. One electron from the 4s orbital is promoted to fill the 3d orbital completely, making the atom more stable.

What does Pauli’s exclusion principle state?

Pauli’s exclusion principle states that no two electrons in the same orbital can have the same set of four quantum numbers. In other words, an orbital can hold a maximum of two electrons, and they must have opposite spins.

How does Hund's rule apply to electron configuration?

Hund's rule states that electrons will fill all available orbitals singly with parallel spins before pairing up in any orbital. This minimizes electron-electron repulsion and provides greater stability.