Struktur Atom (6) | Bilangan Kuantum | utama, azimut, magnetik, spin

Introduction

This tutorial aims to explain the concept of quantum numbers in chemistry, specifically designed for students in grade 10. Quantum numbers are essential for understanding electron configurations in atoms. We will cover the four types of quantum numbers: principal (n), azimuthal (l), magnetic (m), and spin (s), and how to determine them through electron configurations.

Step 1: Understand Quantum Numbers

Quantum numbers are sets of numerical values that describe the unique quantum state of an electron in an atom. There are four types of quantum numbers:

1. Principal Quantum Number (n)

   • Represents the energy level of an electron.
   • Can take positive integer values (1, 2, 3, ...).

2. Azimuthal Quantum Number (l)

   • Indicates the shape of the orbital.
   • Values range from 0 to (n-1).
   • Corresponds to different types of orbitals (s, p, d, f).

3. Magnetic Quantum Number (m)

   • Describes the orientation of the orbital in space.
   • Can take integer values from -l to +l.

4. Spin Quantum Number (s)

   • Indicates the spin of the electron.
   • Can be either +1/2 or -1/2.

Step 2: Determine Electron Configuration

To find quantum numbers, start by learning how to write the electron configuration of an atom. This is the arrangement of electrons in an atom's orbitals.

1. Identify the Element

   • Refer to the periodic table to determine the number of electrons in the neutral atom.

2. Fill the Orbitals

   • Use the Aufbau principle to fill the orbitals from lowest to highest energy:
     • 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, etc.
   • Follow Hund's rule for filling degenerate orbitals (orbitals of the same energy).

3. Example Configuration

   • For oxygen (8 electrons):
     • Configuration: 1s² 2s² 2p⁴

Step 3: Assign Quantum Numbers

Once you have the electron configuration, assign the quantum numbers for each electron:

1. Principal Quantum Number (n)

   • For 1s: n = 1
   • For 2s and 2p: n = 2

2. Azimuthal Quantum Number (l)

   • For s orbital: l = 0
   • For p orbital: l = 1

3. Magnetic Quantum Number (m)

   • For 2p (where l = 1): m can be -1, 0, +1 depending on the specific orbital.

4. Spin Quantum Number (s)

   • Each electron has a spin of +1/2 or -1/2. Assign spins based on the Pauli exclusion principle (no two electrons in the same orbital can have the same spin).

Step 4: Practice with Examples

To solidify your understanding, practice with different elements. Write their electron configurations and determine the quantum numbers for each electron.

1. Example for Carbon (6 electrons)
   • Configuration: 1s² 2s² 2p²
   • Quantum Numbers:
     • 1s electrons: (n=1, l=0, m=0, s=+1/2 and -1/2)
     • 2s electrons: (n=2, l=0, m=0, s=+1/2 and -1/2)
     • 2p electrons: (n=2, l=1, m=-1, 0, +1, assign spins accordingly)

Conclusion

Understanding quantum numbers is pivotal for mastering electron configurations. By following the steps outlined, you can determine the quantum state of electrons in any atom. To further enhance your learning, practice with different elements and refer to the additional resources provided for writing electron configurations.