Difference Between Ammonia and Ammonium Ion

Overview

• Ammonia (NH3) and Ammonium Ion (NH4+)
• Key distinctions include charge, molecular structure, odor, and geometry.

Ammonia (NH3)

• Nature: Neutral molecule (no charge)
• Formula: NH3 (three hydrogens)
• Odor: Strong odor
• Valence Electrons: 5 (N) + 3(1) (H) = 8
• Lewis Structure: 8 valence electrons distributed around nitrogen. Has a lone pair of electrons (2 unbonded electrons).
• Molecular Geometry:
  • Trigonal pyramidal shape due to the lone pair pushing hydrogen atoms downward.
  • Bond Angles: About 107°.

Ammonium Ion (NH4+)

• Nature: Positively charged ion (1+ charge)
• Formula: NH4+ (four hydrogens)
• Odor: Odorless
• Valence Electrons: 5 (N) + 4(1) (H) - 1 (lost electron) = 8
• Lewis Structure: Similar distribution of electrons as ammonia but indicates charge with brackets and a positive sign. No lone pairs of electrons.
• Molecular Geometry:
  • Tetrahedral shape with four hydrogen atoms bonded to nitrogen.
  • Bond Angles: About 109.5°.

Key Differences

• Charge:
  • Ammonia: Neutral
  • Ammonium Ion: Positively charged
• Odor:
  • Ammonia: Strong odor
  • Ammonium Ion: Odorless
• Lone Pairs:
  • Ammonia: Contains lone pair
  • Ammonium Ion: No lone pairs
• Molecular Geometry:
  • Ammonia: Trigonal pyramidal
  • Ammonium Ion: Tetrahedral

Practical Notes

• Ammonia: Available as gas (NH3) or liquid (when cooled enough).
• Ammonium Ion: Does not exist alone; found in compounds like ammonium chloride or dissolved in water.

Additional Links

• Further information on bond angles, molecular geometry, Lewis structures, and hybridization can be found in the description.