Test Unit 6 Chemical Structure

CO₂ has polar bonds but is a NON POLAR molecule. Explain why.

• CO₂ has no symmetrical shape to it, making it nonpolar.

• Bond polarity (or dipole moment) between C and O atoms cancel due to symmetry.

• Bond polarity (or dipole moment) between C and O atoms do not cancel and is stronger to the left side of the molecule.

• Electronegativity of C and O atoms are the same therefore makes the molecule nonpolar.

Identify the molecule that could potentially take this molecular geometry (shape).

• BF₃
• CH₃

• H₃O⁺¹

• CO₂

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Identify the TOTAL number of electrons participating in bonding for the molecule pictured.

• 8

• 6

• 2

• 3

The steric number is used to identify the molecular geometry of a molecule.

Identify the steric number for the molecule pictured (number of bonding plus non-bonding sites).

• 5

• 4

• 3

• 2

Define: Lone-pair electrons

• A pair of bonding electrons on the central atom.

• A single, non-bonding electron on the central atom.

• A pair of bonding electrons on any atom in the molecule.

• A pair of non-bonding electrons on the central atom.

Organize these options into the correct categories

Groups:

(a) Ionic Bond

,

(b) Polar Covalent Bond

,

(c) Non-polar Covalent Bond

• Bond between diatomic elements (Br₂, Cl₂, N₂, O₂ )

• When electrons are shared evenly

• Bond formed between a metal and nonmetal atom

• Bond formed between two DIFFERENT nonmetals

• Formed by ions held together by electrostatic attraction

• When electrons are shared unevenly

• When one atom takes or gives electrons to another atom

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NGSS.HS-PS1-2

Intermolecular forces are the forces...

• within molecules that bond atoms together.

• between molecules causing them to attract.

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Identify the intermolecular force that occurs between two POLAR molecules.

If needed, use the image provided.

• London Dispersion Force

• Dipole-Dipole Force

• Hydrogen bonding Force

• Dark Force

In general, substances with stronger intermolecular forces have ________ boiling points than those with weaker forces

• Higher
• Lower
• Intermolecular Forces have no affect on boiling point.

Water, H₂O, is liquid at room temperature, while hydrogen sulfide, H₂S, is a gas at room temperature. Both have the same Lewis dot structure.

The difference in states of matter could be due to which of the following:

• H₂O has London dispersion forces, while H₂S has dipole-dipole forces.

• H₂O has hydrogen bonding forces, while H₂S only has London dispersion forces.

• H₂O has dipole-dipole forces, while H₂S only has London dispersion forces.

• H₂O has hydrogen bonding forces, while H₂S only has dipole-dipole forces.