KONFIGURASI ELEKTRON MENURUT TEORI ATOM BOHR & ELEKTRON VALENSI (KIMIA SMA KELAS 10)

Introduction

This tutorial provides a step-by-step guide to understanding electron configurations based on Bohr's atomic theory. It is particularly relevant for 10th-grade chemistry students. By the end of this tutorial, you will be able to determine the electron configuration for various elements, including a corrected configuration for bromine (Br).

Step 1: Understanding Bohr's Atomic Theory

• Basics of Bohr's Theory:

  • Electrons orbit the nucleus in defined energy levels or shells.
  • Each shell can hold a maximum number of electrons based on the formula 2n², where n is the shell number.

• Electron Shell Capacities:

  • 1st shell (n=1): 2 electrons
  • 2nd shell (n=2): 8 electrons
  • 3rd shell (n=3): 18 electrons
  • 4th shell (n=4): 32 electrons

Step 2: Writing Electron Configurations

• General Approach:

  • Start filling from the lowest energy level (1st shell) to the highest.
  • Use the maximum number of electrons each shell can hold.

• Example of Electron Configuration:

  • For Carbon (atomic number 6):
    • Fill 1st shell: 2 electrons (2)
    • Fill 2nd shell: 4 electrons (4)
    • Configuration: 2, 4

Step 3: Special Case of Bromine

• Corrected Configuration for Bromine:
  • Atomic number of Br is 35.
  • Fill the shells as follows:
    • 1st shell: 2 electrons
    • 2nd shell: 8 electrons
    • 3rd shell: 18 electrons
    • 4th shell: 7 electrons
  • Configuration: 2, 8, 18, 7

Step 4: Practical Application of Electron Configurations

• Understanding Chemical Properties:

  • The electron configuration determines how an element reacts chemically.
  • Elements with similar configurations in the outer shell (valence electrons) behave similarly.

• Valence Electrons:

  • Focus on the outermost shell's electrons to determine bonding and reactivity.
  • Example: For Br, the valence electrons are 7, which influences its chemical behavior.

Conclusion

In this tutorial, you learned how to write electron configurations using Bohr's atomic theory and understood the significance of valence electrons. The corrected configuration for bromine was also highlighted. To further enhance your understanding, practice writing configurations for other elements and explore how their electron arrangements affect their chemical properties.