Konfigurasi Elektron

Introduction

This tutorial explains the concept of electron configuration, a fundamental topic in chemistry that describes the arrangement of electrons around the nucleus of an atom. Understanding electron configuration is essential for predicting chemical behavior, bonding, and the properties of elements. We will cover the Aufbau principle, Hund's rule, Pauli exclusion principle, and the significance of full and half-full subshells.

Step 1: Understand the Aufbau Principle

The Aufbau principle states that electrons occupy the lowest energy orbitals first before filling higher energy levels. To apply this principle:

• Start filling the orbitals in the following order:
  • 1s
  • 2s
  • 2p
  • 3s
  • 3p
  • 4s
  • 3d
  • 4p
  • 5s
  • 4d
  • 5p
  • 6s
  • 4f
  • 5d
  • 6p
  • 7s
  • 5f
  • 6d
  • 7p

Practical Tip: Use an electron configuration chart to visualize the order of orbital filling.

Step 2: Apply Hund's Rule

Hund's rule states that electrons will fill degenerate orbitals (orbitals with the same energy) singly before pairing up. To follow this rule:

• When filling p, d, or f orbitals, place one electron in each orbital before any orbital gets a second electron.
• This minimizes electron-electron repulsion and leads to a more stable arrangement.

Common Pitfall: Forgetting to follow Hund's rule can lead to incorrect predictions of an atom's reactivity and bonding behavior.

Step 3: Utilize the Pauli Exclusion Principle

The Pauli exclusion principle posits that no two electrons in an atom can have the same set of quantum numbers. To adhere to this principle:

• Each orbital can hold a maximum of two electrons, which must have opposite spins.
• When writing configurations, represent electron spins with arrows (↑ for spin-up and ↓ for spin-down).

Example:

• For the 1s orbital filled with two electrons, represent it as:

  1s²: ↑↓
  

Step 4: Recognize Full and Half-Full Subshells

Full and half-full subshells have special stability due to electron configuration. Here’s how to identify them:

• A full subshell has the maximum number of electrons:
  • s: 2 electrons
  • p: 6 electrons
  • d: 10 electrons
  • f: 14 electrons
• A half-full subshell has exactly half the maximum number of electrons:
  • p: 3 electrons (1 in each of the three orbitals)
  • d: 5 electrons (1 in each of the five orbitals)

Understanding these configurations can help predict the stability of elements and their likelihood to form compounds.

Conclusion

In this tutorial, we covered the basics of electron configuration, focusing on the Aufbau principle, Hund's rule, Pauli exclusion principle, and the importance of full and half-full subshells. To deepen your understanding, consider practicing with various elements and their configurations, and refer to the provided materials for further study. For more advanced topics, explore the implications of electron configurations on chemical bonding and molecular shapes.