IKATAN KIMIA : IKATAN KOVALEN KOORDINASI | KIMIA SMA KELAS 10

Introduction

This tutorial explains the formation of coordinate covalent bonds in molecules, how to write Lewis structures, and how to identify molecular formulas for compounds with coordinate covalent bonds. Understanding these concepts is essential for chemistry students, particularly in Grade 10, as it lays the groundwork for more advanced topics.

Step 1: Understanding Coordinate Covalent Bonds

• A coordinate covalent bond forms when one atom provides both electrons for a shared pair in a bond.
• Commonly seen in complex ions and coordination compounds.
• Example: The bond between ammonia (NH3) and boron trifluoride (BF3) forms a coordinate bond, where nitrogen donates a lone pair of electrons.

Practical Tip

• Look for molecules where one atom has a lone pair of electrons and another atom has an empty orbital. This often indicates the possibility of a coordinate covalent bond.

Step 2: Writing Lewis Structures

• Lewis structures visually represent the arrangement of atoms and their bonding.
• Steps to draw a Lewis structure:
  1. Count the total number of valence electrons in the molecule.
  2. Arrange atoms, placing the least electronegative atom in the center.
  3. Connect atoms with single bonds, using two electrons for each bond.
  4. Distribute remaining electrons to fulfill the octet rule for each atom.
  5. If necessary, form double or triple bonds by sharing lone pairs.

Common Pitfall

• Failing to account for all valence electrons can lead to incorrect Lewis structures. Always double-check your counts.

Step 3: Identifying Molecular and Structural Formulas

• The molecular formula indicates the number and type of atoms in a molecule, while the structural formula shows how these atoms are connected.
• To derive the formulas:
  1. From the Lewis structure, count the types of atoms present.
  2. Write the molecular formula based on these counts.
  3. For the structural formula, ensure that the arrangement of bonds matches the Lewis structure.

Real-World Application

• Understanding these formulas is crucial in predicting the behavior of molecules in chemical reactions and their interactions in biological systems.

Step 4: Examples of Coordinate Covalent Compounds

• Familiarize yourself with common compounds that exhibit coordinate covalent bonds:
  • Ammonium ion (NH4+): Formed from ammonia and a proton (H+).
  • Complex ions like [Cu(NH3)4]2+: Copper ion coordinated by four ammonia molecules.

Practical Tip

• Try to visualize the 3D structure of these compounds to better understand how coordinate bonds influence molecular geometry.

Conclusion

In this tutorial, we covered the fundamentals of coordinate covalent bonds, how to write Lewis structures, and how to derive molecular and structural formulas. Mastering these concepts is essential for further studies in chemistry. To deepen your understanding, consider exploring additional resources or videos on related topics such as ionic bonds, polar and nonpolar covalent bonds, and exceptions to the octet rule.