Question

For future reference, you would want to draw the Lewis structure for each of these simple molecules, determine the geometry, and look to see if the molecule is symmetrical or not. A symmetrical molecule is nonpolar with a dipole moment of zero, while an asymmetrical molecule has a net dipole moment and is polar. You may have noticed that the compounds are listed in terms of increasing electron pair geometry complexity of the central atom, and with the molecular geometry that corresponds to the electron pair geometry.

A) H₂O
B) CO₂
C) CH₄
D) NH₃

Answer 1

The Lewis structures, geometries, and polarity of H₂O, CO₂, CH₄, and NH₃.

Step-by-step explanation:

A) H₂O: The Lewis structure of H₂O consists of two hydrogen atoms bonded to an oxygen atom. The geometry of H₂O is bent, with a bond angle of approximately 104.5°. Since the molecule is asymmetrical, it has a net dipole moment and is polar.

B) CO₂: The Lewis structure of CO₂ consists of a carbon atom double bonded to two oxygen atoms. The geometry of CO₂ is linear, with a bond angle of 180°. Since the molecule is symmetrical, it has no net dipole moment and is nonpolar.

C) CH₄: The Lewis structure of CH₄ consists of four hydrogen atoms bonded to a carbon atom. The geometry of CH₄ is tetrahedral, with bond angles of approximately 109.5°. Since the molecule is symmetrical, it has no net dipole moment and is nonpolar.

D) NH₃: The Lewis structure of NH₃ consists of three hydrogen atoms bonded to a nitrogen atom. The geometry of NH₃ is trigonal pyramidal, with a bond angle of approximately 107°. Since the molecule is asymmetrical, it has a net dipole moment and is polar.