Questions and Answers
What is the Lewis structure of CH4 (methane)?
What is the electron geometry of CH4?
Tetrahedral
What is the molecular geometry of CH4?
Tetrahedral
What is the bond angle of CH4?
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What is the Lewis structure of NH3 (ammonia)?
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What is the electron geometry of NH3?
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What is the molecular geometry of NH3?
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What is the bond angle of NH3?
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What is the Lewis structure for OH2 (water)?
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What is the electron geometry of OH2?
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What is the molecular geometry of OH2?
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What is the bond angle of OH2?
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What is the Lewis structure for CO2 (carbon dioxide)?
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What is the electron geometry of CO2?
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What is the molecular geometry of CO2?
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What is the definition of electron geometry?
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What is the definition of molecular geometry?
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What does ABE stand for?
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What is the angle of trigonal planar (AB3)?
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What is the angle of trigonal bent (AB2E)?
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What is the bond angle of tetrahedral (AB4)?
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What is the bond angle of trigonal pyramidal (AB3E)?
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What is the bond angle of tetrahedral bent (AB2E2)?
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What is the bond angle of trigonal bipyramidal (AB5)?
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What is the bond angle of seesaw/irregular tetrahedron (AB4E)?
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What is the bond angle of linear (AB2)?
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What is the bond angle of T-shape?
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What is the bond angle of 5-domain linear?
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What is the bond angle of octahedral (AB6)?
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What is the bond angle of square pyramidal (AB5E)?
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What is the bond angle of square planar (AB4E2)?
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How do you determine hybridization?
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What is the name for the first bond (s orbital)?
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What is the name for the 2nd and 3rd bonds (p orbitals)?
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Study Notes
Lewis Structures of Molecules
- CH4 (methane) has a Lewis structure showing 4 single bonds connecting the carbon atom to four hydrogen atoms.
- NH3 (ammonia) features a Lewis structure with 3 single bonds connecting nitrogen to three hydrogen atoms, plus one lone pair.
- OH2 (water) consists of a Lewis structure with 2 single bonds connecting oxygen to two hydrogen atoms, plus two lone pairs.
- CO2 (carbon dioxide) is depicted with a Lewis structure showing 2 double bonds between carbon and two oxygen atoms.
Electron Geometry
- CH4 exhibits tetrahedral electron geometry due to four electron domains surrounding the carbon atom.
- NH3 also demonstrates tetrahedral electron geometry despite having a lone pair, affecting its molecular shape.
- OH2 shares the same tetrahedral electron geometry but is impacted by two lone pairs on the oxygen atom.
- CO2 presents linear electron geometry as it has only two bonding pairs with no lone pairs.
Molecular Geometry
- CH4 has tetrahedral molecular geometry, aligning with its electron geometry.
- NH3's molecular geometry is trigonal pyramidal due to the presence of a lone pair pushing the hydrogen atoms downward.
- OH2 has a bent/angular molecular geometry attributed to two lone pairs repelling the bonded hydrogen atoms.
- CO2 retains linear molecular geometry, reflecting its structure.
Bond Angles
- The bond angle in CH4 is 109.5°, characteristic of tetrahedral arrangements.
- NH3 has a bond angle of 107°, slightly reduced from tetrahedral due to the influence of the lone pair.
- OH2 exhibits a smaller bond angle of 105°, resulting from the strong repulsion between the two lone pairs.
- CO2 has a bond angle of 180° due to its linear structure.
ABE Notation
- ABE notation is a method to analyze molecular structure:
- A = total number of electron domains
- B = number of bonded electron domains
- E = number of lone pairs.
Molecular Geometries and Bond Angles
- Trigonal planar (AB3) has bond angles of 120°.
- Trigonal bent (AB2E) features bond angles of 120°.
- Tetrahedral (AB4) maintains bond angles of 109.5°.
- Trigonal pyramidal (AB3E) typically shows bond angles of 107°.
- Tetrahedral bent (AB2E2) has bond angles around 105°.
- Trigonal bipyramidal (AB5) involves bond angles of both 90° and 120°.
- Seesaw/irregular tetrahedron (AB4E) retains bond angles of 90° and 120°.
- Linear (AB2) has a bond angle of 180°.
- T-shape geometry corresponds to bond angles of 90°.
- Octahedral (AB6) features 90° bond angles.
- Square pyramidal (AB5E) and square planar (AB4E2) both have bond angles of 90°.
Hybridization
- Hybridization is determined by the number of electron domains:
- 1 electron domain = s
- 3 electron domains = p
- 5 electron domains = d
- Molecules like AB4, AB3E, and AB2E2 exhibit sp³ hybridization;
- Molecules such as AB5, AB4E, AB3E2, and AB2E3 show sp³d hybridization;
- AB6, AB5E, and AB4E2 have sp³d² hybridization.
Bond Types
- The first bond formed in a molecular interaction is a sigma bond, typically involving s orbitals.
- Additional bonds, such as the second and third, are classified as pi bonds, primarily involving p orbitals.
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Description
Test your understanding of Lewis structures and electron geometries for common molecules like methane, ammonia, water, and carbon dioxide. This quiz covers both their Lewis structures and the associated molecular and electron geometries. Perfect for chemistry students looking to reinforce their knowledge!
