VSEPR Theory and Molecular Geometry Quiz
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Questions and Answers

What does VSEPR stand for?

  • Valence Shield Electron Pair Repulsion
  • Valence Shell Electron Pair Rejection
  • Valence Shell Effective Pair Repulsion
  • Valence Shell Electron Pair Repulsion (correct)

What is the basic fact that determines molecular shapes?

Electron pairs repel each other

What is the electron geometry of NH3 (ammonia)?

Tetrahedral

Under what condition is the electronic arrangement the same as the molecular shape?

<p>When there are no lone pairs of electrons on the central atom</p> Signup and view all the answers

What is the molecular geometry of ammonia (NH3)?

<p>Trigonal pyramidal</p> Signup and view all the answers

Why is the bond angle of H2O less than the tetrahedral bond angle of 109.5 degrees?

<p>The repulsion between lone pairs of electrons is greater than the repulsion between bonding pairs</p> Signup and view all the answers

What arrangement of atoms occurs when the central atom is covalently bonded to five other atoms without nonbonding electrons?

<p>Trigonal bipyramidal</p> Signup and view all the answers

All non-polar molecules have non-polar bonds.

<p>False (B)</p> Signup and view all the answers

Which molecular geometry is possible with 0, 3, or 4 lone pairs?

<p>Linear</p> Signup and view all the answers

What is the electronic geometry of SF6?

<p>Octahedral</p> Signup and view all the answers

What is the molecular geometry of SF6?

<p>Octahedral</p> Signup and view all the answers

Is SF6 polar?

<p>False (B)</p> Signup and view all the answers

How many lone pairs are on the central atom in SF6?

<p>0</p> Signup and view all the answers

What is the electronic geometry of HCN?

<p>Linear</p> Signup and view all the answers

What is the molecular geometry of HCN?

<p>Linear</p> Signup and view all the answers

Is HCN polar?

<p>False (B)</p> Signup and view all the answers

How many total lone pairs are present in HCN?

<p>One</p> Signup and view all the answers

What is the electronic geometry of SCl4?

<p>Trigonal bipyramidal</p> Signup and view all the answers

What is the molecular geometry of SCl4?

<p>See-saw</p> Signup and view all the answers

Is SCl4 polar?

<p>False (B)</p> Signup and view all the answers

How many lone pairs are on the central atom/total lone pairs in SCl4?

<p>1, 3</p> Signup and view all the answers

What is the electronegativity of hydrogen?

<p>About equal to that of carbon</p> Signup and view all the answers

Predict the bond angle for a 3-atom molecule A-B-A where B has only four valence electrons.

<p>180 degrees</p> Signup and view all the answers

What is the molecular geometry of COCl2?

<p>Trigonal planar</p> Signup and view all the answers

What is the molecular geometry of the ion NO2-?

<p>Bent or angular</p> Signup and view all the answers

What is the electronic and molecular geometry of IF4-?

<p>Octahedral, square planar</p> Signup and view all the answers

Is IF4- non-polar?

<p>False (B)</p> Signup and view all the answers

How many other atoms can a central atom that is sp3 hybridized bind to?

<p>4</p> Signup and view all the answers

Flashcards

VSEPR

Valence Shell Electron Pair Repulsion theory. A model used to predict the shape of molecules based on the repulsion between electron pairs.

Molecular Shape

The 3-dimensional arrangement of atoms in a molecule.

Electron Pair Repulsion

The fundamental force that determines molecular shapes

NH3 electron geometry

Tetrahedral

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Identical electronic/molecular geometry

Occurs when there are no lone pairs on the central atom.

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NH3 molecular geometry

Trigonal Pyramidal

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H2O bond angle

Less than 109.5 degrees (bent shape).

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Trigonal bipyramidal

5 atoms bonded to the central atom, no lone pairs.

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Non-polar molecule, non-polar bonds

False. Non-polar molecules can have polar bonds.

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Linear molecular geometry

Possible with 0, 3, or 4 lone pairs.

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SF6 electronic geometry

Octahedral

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SF6 molecular geometry

Octahedral

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SF6 polarity

Non-polar

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SF6 lone pairs

0 lone pairs.

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HCN electronic geometry

Linear

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HCN molecular geometry

Linear

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HCN polarity

Polar

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HCN lone pairs

One

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SCl4 electronic geometry

Trigonal bipyramidal

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SCl4 molecular geometry

See-saw

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SCl4 polarity

Polar

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SCl4 lone pairs

1 lone pair

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COCl2 molecular geometry

Trigonal planar

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NO2- molecular geometry

Bent

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IF4- electronic geometry

Octahedral

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IF4- molecular geometry

Square planar

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IF4- polarity

Polar

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sp3 hybridized central atom bonding

Four atoms

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Study Notes

VSEPR Theory

  • VSEPR stands for valence shell electron pair repulsion.
  • Molecular shapes are determined by the repulsion between electron pairs.

Molecular Geometry

  • Ammonia (NH3) has a tetrahedral electron geometry.
  • Ammonia's molecular geometry is trigonal pyramidal due to one lone pair on the central atom.
  • Without lone pairs on the central atom, electronic arrangement equals molecular shape.

Bond Angles

  • The bond angle in H2O is less than 109.5 degrees due to stronger repulsion from lone pairs compared to bonding pairs.
  • A 3-atom molecule (A-B-A) with B having four valence electrons will result in a bond angle of 180 degrees.

Central Atom Hybridization

  • A central atom covalently bonded to five atoms without nonbonding electrons exhibits a trigonal bipyramidal arrangement.
  • An sp3 hybridized central atom can bind to four other atoms.

Molecular Structures and Polarity

  • SF6 has octahedral electronic and molecular geometry; it is nonpolar.
  • HCN has linear geometry and is polar.
  • SCl4 has a trigonal bipyramidal electronic geometry and seesaw molecular geometry; it is polar.
  • IF4 has octahedral electronic geometry and square planar molecular geometry; it is nonpolar.
  • Not all nonpolar molecules consist of nonpolar bonds.

Electron Pairs in Molecules

  • Total lone pairs in molecules varies; for SF6, there are 0 central lone pairs and 18 total, and for SCl4, there is 1 central lone pair and 3 total.
  • COCl2 has a trigonal planar molecular geometry.
  • The ion NO2- has a bent or angular molecular geometry.

Electronegativity

  • The electronegativity of hydrogen (H) is roughly equal to that of carbon (C).

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Description

Test your understanding of VSEPR theory, molecular geometry, and bond angles. This quiz covers topics like hybridization, bond angles in different molecular structures, and the shape of molecules based on electron repulsion. See how much you know about the spatial arrangement of molecules!

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