Question 1

Which of the following best describes the equatorial position in a molecule with 5 or 6 electron groups around the central atom?

Accepted Answer

It is the position around the equator of the compound, maximizing separation between electron groups.

Question 2

In a molecule with 5 electron groups (trigonal bipyramidal geometry), where do lone pairs preferentially reside and why?

Accepted Answer

In the equatorial position, because it minimizes 90° interactions with other electron groups.

Question 3

Which of the following statements about the molecular geometry of $$\mathrm{PF_5$} is $$correct?

Accepted Answer

$$\mathrm{PF_5$}$$ has a trigonal bipyramidal geometry with all positions occupied by bonding pairs.

Question 4

For the ion $$\mathrm{$$SCl_4$$^+}$$, what is the most likely molecular geometry?

Accepted Answer

Seesaw

Question 5

Why do lone pairs prefer the equatorial position in a trigonal bipyramidal geometry?

Accepted Answer

Because the equatorial position minimizes repulsion by having fewer 90° interactions with other electron groups.

Question 6

A molecule has 6 electron groups around the central atom. According to VSEPR theory, what is the most stable position for a lone pair?

Accepted Answer

Any position, as all positions are equivalent in an octahedral geometry

Question 7

Which of the following best explains why the most electronegative element tends to prefer the axial position over the equatorial position in a trigonal bipyramidal geometry?

Accepted Answer

Because the axial position has more repulsion, which the electronegative atom can better tolerate.

Question 8

Given the molecule $$\mathrm{$$XeF_4$$}$$, what is its molecular geometry and why?

Accepted Answer

Square planar, because two lone pairs occupy positions opposite each other in an octahedral arrangement.

Question 9

How many lone pairs reside in the equatorial position of the $$\mathrm{$$KCl_3$$^{2-}}$$ ion?

Accepted Answer

2

Question 10

A molecule has 5 electron groups: 3 bonding pairs and 2 lone pairs. What is its molecular geometry?

Accepted Answer

T-shaped

Question 11

Which of the following is the correct Lewis structure for $$\mathrm{Br_2CO}$$?

Accepted Answer

Br atoms are bonded to C, which is double bonded to O, with all atoms obeying the octet rule.

Question 12

Which of the following best describes the difference between axial and equatorial positions in a trigonal bipyramidal geometry?

Accepted Answer

Axial positions are perpendicular to the equatorial plane and 180° apart, while equatorial positions are 120° apart in the same plane.

Question 13

If a molecule has 6 electron groups and 1 lone pair, what is its molecular geometry?

Accepted Answer

Square pyramidal

Question 14

Which of the following is a correct statement about lone pair positions in molecules with 5 or 6 electron groups?

Accepted Answer

Lone pairs prefer equatorial positions in 5-group systems, but any position in 6-group systems.

Question 15

Which of the following best explains why $$\mathrm{Br_2CO} is a $$planar molecule?

Accepted Answer

Because the central carbon is sp$$^2$$ hybridized, resulting in a trigonal planar arrangement.

Molecular Geometry: Axial and Equatorial Positions, Lone Pair Placement, and Practice Problems

Study Guide - Practice Questions

Study Guide - Flashcards