Questions and Answers
What are the steps for predicting molecular polarity?
What two factors do polarity depend on?
Symmetry and Bond Polarity
Non polar molecules have positive and negative sides.
False
A symmetrical molecule is always non polar.
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Molecules with no shared electrons are called?
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Bent molecules are always polar.
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What is the shape of a trigonal planar molecule?
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Can a molecule be asymmetrical if the shape is the same but one atom is different?
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What is VSEPR?
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What are VSEPR groups used for?
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What does molecular geometry depend on?
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Molecules with 2 VSEPR electron groups are identified as?
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Molecules with 3 VSEPR electron groups are known as?
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Molecules with 4 VSEPR electron groups can be?
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What is the electron domain geometry for 0:3?
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What is the electron domain geometry for 0:4?
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What is the electron domain geometry for 1:3?
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What is the electron domain geometry for 2:2?
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What is the electron domain geometry for 0:2?
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Study Notes
Molecular Polarity Basics
- Molecular polarity is determined by bond polarity and molecular symmetry.
- A molecule is classified as molecular if it is composed only of nonmetals and involves shared electrons.
Steps for Predicting Molecular Polarity
- Check if the molecule contains polar covalent bonds.
- If polar bonds are present, assess their arrangement: asymmetry indicates polarity, while symmetry results in non-polarness.
Characteristics of Polar and Non-Polar Molecules
- Polar molecules exhibit partial positive and negative charges due to uneven electron sharing.
- Non-polar molecules lack distinct charged sides and can be symmetrical or have no shared electrons.
- Molecules with only carbon and hydrogen are inherently non-polar.
Molecular Geometry and Polarity
- Bent and trigonal pyramidal molecular shapes are always polar due to asymmetry.
- Trigonal planar and tetrahedral structures can be polar or non-polar depending on symmetry.
- Linear geometries can also be polar or non-polar based on symmetrical arrangements.
VSEPR Theory
- VSEPR (Valence Shell Electron Pair Repulsion) Theory predicts molecular shapes based on electron group arrangements.
- The geometries depend on the number of electron groups around the central atom, influencing bond angles.
Specific Molecular Geometries
- Linear Geometry: 2 VSEPR electron groups, 180° angles, non-polar or polar depending on symmetry.
- Trigonal Planar: 3 VSEPR groups, ~120° angles, polar or non-polar based on bond arrangement.
- Tetrahedral: 4 VSEPR groups, 109.5° angles, can yield bent or trigonal pyramidal shapes based on lone pair presence.
- Bent Geometry: Always asymmetrical, thus inherently polar.
Electron Group Arrangements
- 0 : 3 VSEPR groups results in a trigonal planar molecular geometry.
- 0 : 4 results in a tetrahedral molecular geometry.
- 1 : 3 yields a trigonal pyramidal shape.
- 2 : 2 creates a bent structure in a tetrahedral electron domain.
Key Takeaways
- Always assess shape symmetry and bond polarity to determine molecular polarity.
- The arrangement of electrons and atoms greatly affects molecular characteristics and behaviors.
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Description
Test your understanding of molecular polarity with this quiz! Learn about bond polarity, molecular symmetry, and how these factors influence whether a molecule is polar or non-polar. Cover various molecular geometries and characteristics of molecules in detail.
