Naming and Drawing Covalent Molecules

Introduction

Covalent molecules consist of two or more nonmetals that share electrons. Proper naming and drawing of these molecules are essential for clear communication in chemistry.

Naming Covalent Molecules

1. Prefix System: Use prefixes to indicate the number of atoms of each element.
   • Mono- (1), Di- (2), Tri- (3), Tetra- (4), Penta- (5), Hexa- (6), Hepta- (7), Octa- (8), Nona- (9), Deca- (10)
2. Naming Convention: The first element retains its name, while the second element's name is modified to end with -ide.
   • Example: CO₂ is named carbon dioxide.

Example Naming

• N₂O: Dinitrogen monoxide
• SF₆: Sulfur hexafluoride

Drawing Covalent Molecules

1. Lewis Structures: To draw a covalent molecule:
   • Count total valence electrons.
   • Arrange atoms with bonds between them.
   • Distribute remaining electrons to satisfy the octet rule.

Example Drawing

• For water (H₂O):
  1. Total valence electrons = 2 (H) + 6 (O) = 8.
  2. H-O-H structure is drawn with single bonds.

Key Questions

• What prefixes are used in naming covalent molecules?
• How do you determine the number of valence electrons in a molecule?
• Why do we modify the second element's name to end with -ide?

Conclusion

Understanding the naming and drawing of covalent molecules is crucial for effective communication in chemistry. Practice with various molecules to solidify these concepts.

References

• Chemistry textbooks on molecular structures
• Online resources for molecular visualization