Konfigurasi Elektron dan Elektron Valensi Part 1

Introduction

In this tutorial, we will explore the concept of electron configuration and valence electrons based on the Bohr model of the atom. This topic is crucial for understanding the behavior of elements in chemistry, especially for students in their first year of high school. We will break down the steps to determine electron configurations and identify valence electrons in a way that is easy to follow and apply.

Step 1: Understand the Bohr Model

The Bohr model provides a simplified view of the atom, where electrons orbit the nucleus in defined paths or energy levels. To grasp electron configuration, it is important to:

• Familiarize yourself with the structure of an atom, which consists of protons, neutrons, and electrons.
• Recognize that electrons are arranged in energy levels (also known as shells) around the nucleus.

Key Points

• The first energy level can hold up to 2 electrons.
• The second energy level can hold up to 8 electrons.
• The third energy level can hold a maximum of 18 electrons but is usually filled to 8 for the purpose of basic configurations.

Step 2: Determine Electron Configuration

Electron configuration describes the distribution of electrons among the energy levels and orbitals. Follow these steps to determine the electron configuration of an element:

1. Identify the atomic number of the element, which tells you the total number of electrons.
2. Fill the energy levels in the following order:
   • 1s
   • 2s
   • 2p
   • 3s
   • 3p
   • 4s
   • 3d
   • 4p
   • 5s (and so on)
3. Apply the Aufbau principle, which states that electrons occupy the lowest energy orbitals first.

Example

For Carbon (atomic number 6):

• The electron configuration would be 1s² 2s² 2p².

Step 3: Identify Valence Electrons

Valence electrons are the electrons in the outermost shell and are crucial for determining an element's chemical properties. To find the valence electrons:

1. Locate the highest energy level filled with electrons.
2. Count the electrons in that energy level.

Practical Advice

• For elements in groups 1 and 2 of the periodic table, the number of valence electrons corresponds to the group number.
• For groups 13 to 18, subtract 10 from the group number to find the valence electrons.

Example

For Carbon again:

• The highest energy level is 2 (from 1s² 2s² 2p²), and it has 4 valence electrons.

Conclusion

In this guide, we covered the basics of the Bohr model, how to determine electron configurations, and how to identify valence electrons. Understanding these concepts is essential for further studies in chemistry, including bonding and chemical reactions.

Next steps may include practicing with different elements to solidify your understanding of electron configurations and valence electrons. This foundational knowledge will support your learning as you progress in chemistry.