Molecular Geometry and Bond Angles Quiz

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What is the shape of a molecule with the formula AX₂E₂ and what is its approximate bond angle?

The shape is bent or V-shaped with an approximate bond angle of 104.5°.

Describe the molecular shape and bond angles of PCl₅.

PCl₅ forms a trigonal bipyramidal shape with bond angles of 120° and 90°.

What defines the octahedral shape of SF₆ and what are the bond angles?

SF₆ has six bonding pairs around the central sulfur atom, resulting in an octahedral shape with bond angles of 90°.

Explain the concept of expanded octet and which elements demonstrate this phenomenon.

Expanded octet refers to atoms having more than eight valence electrons, exhibited by elements in the third period and beyond. Signup and view all the answers

What causes the deviation from the ideal tetrahedral angle in AX₂E₂ molecules?

The deviation is caused by lone-pair-lone-pair, lone-pair-bond pair, and bond-pair-bond pair repulsions. Signup and view all the answers

What is the definition of bond energy?

Bond energy is the amount of energy required to break one mole of bonds. Signup and view all the answers

Describe the shape and bond angle of molecules with two electron pairs around the central atom.

Molecules with two electron pairs have a linear shape with a 180° bond angle. Signup and view all the answers

What is the Lewis structure of BeF₂ and what shape does it represent?

The Lewis structure is <code>:F—Be—F:</code> and it represents a linear shape. Signup and view all the answers

What shape and bond angle do molecules with three electron pairs around the central atom exhibit?

Molecules with three electron pairs exhibit a trigonal planar shape with a 120° bond angle. Signup and view all the answers

What contributions do the atoms in BCl₃ make to its Lewis structure?

Boron contributes three valence electrons, while each Chlorine contributes seven valence electrons. Signup and view all the answers

How does the presence of lone pairs affect the shape of a molecule compared to bonding pairs?

Lone pairs occupy more space due to their concentrated electron charge, causing greater repulsion which alters the geometry of the molecule compared to bonding pairs. Signup and view all the answers

What role does the Valence Shell Electron Pair Repulsion Theory play in understanding molecular geometry?

It explains that electron pairs repel each other, influencing the arrangement and angles between bonds to minimize repulsive forces. Signup and view all the answers

Why is it important to consider both bonding and lone electron pairs when predicting molecular shape?

Both types of pairs influence the overall electron cloud repulsion, which affects bond angles and hence the molecular structure. Signup and view all the answers

In terms of electron repulsion, how do bonding pairs differ from lone pairs?

Bonding pairs are shared between atoms, while lone pairs are not involved in bonding and create stronger repulsion due to their localized electron concentration. Signup and view all the answers

What factors determine the bond angles in a molecule according to VSEPR theory?

Bond angles are determined by the number of electron pairs around the central atom and the arrangement of bonding versus lone pairs. Signup and view all the answers

What is the molecular geometry of SO2 and how does the presence of a lone pair affect this shape?

The molecular geometry of SO2 is bent or V-shaped due to the presence of a lone pair which increases repulsion between bonding pairs. Signup and view all the answers

Describe the electron pair arrangement in CH4 and its resulting molecular shape.

In CH4, the electron pair arrangement is tetrahedral as it has four bonding pairs and no lone pairs, resulting in bond angles of 109.5°. Signup and view all the answers

What type of molecular shape does NH3 exhibit, and how does the lone pair influence the bond angles?

NH3 exhibits a trigonal pyramidal shape, and the lone pair reduces the H-N-H bond angles from the ideal 109.5° due to repulsion. Signup and view all the answers

Explain the significance of the notation AX2E in the context of SO2.

The notation AX2E indicates that SO2 has two bonding pairs (A) and one lone pair (E), which defines its geometry as bent. Signup and view all the answers

How does the presence of lone pairs versus bonding pairs influence molecular shapes like that of SO2 and NH3?

Lone pairs occupy more space than bonding pairs, leading to greater repulsions which alter the bond angles and molecular shape. Signup and view all the answers

Valence Shell Electron Pair Repulsion

A theory to predict the shape of molecules by considering the repulsions between electron pairs around a central atom.

Electron repulsion in molecules

Electron pairs in bonds or lone pairs repel each other, leading to specific molecular shapes.