This question examines VSEPR theory for molecules with expanded octets and five electron domains. In PCl5, phosphorus has five electron domains from bonds to chlorine and no lone pairs, leading to a trigonal bipyramidal electron-domain and molecular geometry. The three equatorial and two axial positions minimize repulsion among the bonding pairs. This shape is typical for AX5 systems in VSEPR notation. Choice D, octahedral, might tempt those confusing five domains with six, a misconception from miscounting bonds. Consistently use the AXE notation, where A is the central atom, X is a bond, and E is a lone pair, to predict geometries accurately.

This question tests your ability to determine molecular geometry using VSEPR theory. In CO₂, carbon has 2 C-O bonds and 0 lone pairs, giving it 2 electron domains total. With only 2 electron domains and no lone pairs, both the electron-domain geometry and molecular geometry are linear, with a bond angle of 180°. Students sometimes incorrectly choose bent (choice A), confusing CO₂ with molecules like H₂O that have lone pairs. Remember: molecules with 2 electron domains and no lone pairs are always linear.

This question tests molecular geometry for linear arrangements in five-domain systems. In XeF2, xenon has five electron domains: two bonds and three lone pairs. Electron geometry trigonal bipyramidal, molecular linear with lone pairs equatorial. Opposite bonds align linearly. A tempting distractor is choice B, T-shaped, which is for two lone pairs, miscounting lone pairs. Maximize lone pair separation for correct molecular shape.

This question assesses understanding of molecular geometry using VSEPR theory for molecules with multiple bonds. In CO2, the carbon atom has two electron domains from the two C=O double bonds and no lone pairs, resulting in a linear electron-domain geometry. Since there are no lone pairs, the molecular geometry is also linear, with the oxygen atoms positioned 180 degrees apart to minimize repulsion. This configuration is consistent with the VSEPR model for AX2 systems. A common distractor is choice A, bent, which might tempt those miscounting double bonds as separate domains, a misconception that overlooks how each multiple bond counts as a single electron domain. A useful strategy is to draw the Lewis structure first to accurately identify the number of electron domains before predicting geometry.

This question tests your understanding of molecular geometry for molecules with 6 electron domains. In BrF₅, bromine has 5 Br-F bonds and 1 lone pair, giving it 6 electron domains total with an octahedral electron-domain geometry. With one lone pair, the lone pair occupies one position of the octahedron, leaving the 5 fluorine atoms in a square pyramidal arrangement (4 in a square base, 1 at the apex). Students often incorrectly choose trigonal bipyramidal geometry (choice A), miscounting the electron domains as 5 instead of 6. Remember: 6 electron domains with 1 lone pair always results in a square pyramidal molecular geometry.

This question tests molecular geometry prediction using VSEPR for expanded octets. In SF4, sulfur has five electron domains: four bonds and one lone pair. The electron-domain geometry is trigonal bipyramidal, but the lone pair in an equatorial position yields a seesaw molecular geometry. This minimizes 90-degree repulsions. A tempting distractor is choice A, trigonal bipyramidal, which ignores the lone pair's effect, a misconception of confusing electron and molecular geometries. Always distinguish between electron-domain and molecular geometries by accounting for lone pairs.

This question evaluates VSEPR theory for hypervalent molecules with multiple lone pairs. In XeF2, xenon has five electron domains: two bonding pairs and three lone pairs, forming a trigonal bipyramidal electron-domain geometry. The molecular geometry is linear because the lone pairs occupy the three equatorial positions, leaving the fluorine atoms in axial positions 180 degrees apart. This arrangement reduces repulsion effectively. Choice D, trigonal bipyramidal, tempts those who forget lone pairs don't contribute to molecular geometry, a misconception of including non-bonding electrons in atom arrangements. A key strategy is to identify the electron-domain geometry first, then remove lone pairs to visualize the molecular shape.

This question tests your understanding of electron-domain geometry. In BF₃, boron has 3 B-F bonds and 0 lone pairs, giving it 3 electron domains total. Three electron domains arrange themselves in a trigonal planar geometry with 120° bond angles to minimize electron-electron repulsion. Students sometimes incorrectly choose tetrahedral (choice C), perhaps thinking all molecules follow the octet rule, but boron is an exception and is stable with only 6 valence electrons. Remember: electron-domain geometry depends only on the total number of electron domains, regardless of whether they are bonds or lone pairs.

This question tests your understanding of both electron-domain and molecular geometries. In H₂O, oxygen has 2 O-H bonds and 2 lone pairs, giving it 4 electron domains total with a tetrahedral electron-domain geometry. However, the molecular geometry only considers the positions of atoms, so with 2 bonded atoms and 2 lone pairs, the molecular shape is bent with a bond angle of approximately 104.5°. Students often incorrectly choose trigonal planar geometry (choice A), forgetting that water has 4 electron domains, not 3. Remember: 4 electron domains with 2 lone pairs always results in a bent molecular geometry.

This question tests your ability to determine hybridization from molecular structure. In PCl₅, phosphorus has 5 P-Cl bonds and 0 lone pairs, giving it 5 electron domains total with a trigonal bipyramidal geometry. Five electron domains require five hybrid orbitals, which means sp³d hybridization (one s orbital + three p orbitals + one d orbital = five sp³d hybrid orbitals). Students often incorrectly choose sp³ (choice A), forgetting that phosphorus can expand its octet and use d orbitals. Remember: the number of hybrid orbitals must equal the number of electron domains.