Topic 6.5: VSEPR and Molecular Structures WITH Polarity

Bond dipole direction points from the

• central atom outward along every bond

• atom with lone pair to atom without lone pair

• less electronegative atom to more electronegative atom

• larger atom toward the smaller atom

Which molecules are polar under VSEPR and electronegativity considerations?

• NH3 with trigonal pyramidal geometry

• CO2 with linear symmetric geometry

• CF4 with symmetrical tetrahedral shape

• CH3Cl with one C–Cl polar bond

Tags

NGSS.HS-PS1-3

Using VSEPR, what is the geometry around nitrogen in NH3 and its polarity outcome?

• Trigonal planar; nonpolar by symmetry

• Trigonal pyramidal; polar net dipole

• Tetrahedral; nonpolar overall

• Bent; nonpolar due to cancellation

CF4 is nonpolar because

• carbon has no lone pairs causing zero dipole

• all C–F bonds are nonpolar by electronegativity

• its tetrahedral dipoles cancel symmetrically

• fluorine lone pairs cancel central dipole

In CH3Cl, which factor prevents dipole cancellation?

• Linear arrangement of all bonds

• Asymmetric substitution around carbon atom

• Presence of equal C–H and C–Cl bond dipoles

• Zero electronegativity difference in bonds

Label the molecule accordingly.

a

b

Lower electron probability

Higher electron probability

This molecule has a ​​ (a)   shape and is considered (b)   .

• polar
• nonpolar
• linear
• trigonal planar
• tetrahedral
• trigonal pyramidal
• ionic
• bent

A molecule that has ​ (a)   is likely to be non-polar

• high symmetry
• low symmetry
• a chemical structure
• a nitrogen atom

Will this molecule be polar or nonpolar? H₂S

• polar
• nonpolar

Tags

NGSS.HS-PS1-2

Will this molecule be polar or nonpolar? CCl₄

• polar
• nonpolar