VSPR reading

True or false: When using VSEPR theory to determine molecular shape, a triple bond counts as a single electron domain even though it consists of 3 shared electron pairs.

T

Select all the options that correctly describe the bond angles associated with each electron-domain geometry.

The trigonal bipyramidal system has two different bond angles. A species with 3 electron domains will exhibit an ideal bond angle of 120o. A bond angle of 180o is observed for a linear system.

Select all the statements that correctly describe the bonding and geometry in the polyatomic ion SeCl5-.

There are 6 electron domains around the central atom. There is one lone pair on the central atom. The molecular geometry is square pyramidal.

Select all the statements that correctly describe how to determine the molecular shape of a species using VSEPR.

Use the molecular formula to draw the Lewis structure. If unshared electron pairs are present, the molecular geometry will differ from the electron-domain geometry. The total number of shared and unshared electron pairs around the central atom gives the electron-domain geometry.

Molecular geometry is specified for a central atom in a structure. A "central" atom is _____.

any atom that is bonded to two or more other atoms

Select all that apply Which of the marked positions would a single lone pair prefer to occupy? Select all that apply. a c I / I . / b ------- . / I \ I \ I \ e d

b c d

Select all the lettered options that correspond to equatorial positions in the image shown. a c I / I . / b ------- . / I \ I \ I \ e d

b c d

Which of the following correctly describes the bond angle in a molecule of the general type ABx?

c

Match each number of electron domains with the correct electron-domain geometry.

linear: 2 domains trigonal planar: 3 domains tetrahedral: 4 domains trigonal bipyramidal: 5 domains octahedral: 6 domains

Match each molecular geometry correctly to the electron-domain arrangement described. Instructions

linear: 5 electron domains; 3 lone pairs seesaw: 5 electron domains; 1 lone pair square planar: 6 electron domains; 2 lone pairs bent: 4 electron domains; 2 lone pairs trigonal pyramidal: 4 electron domains; 1 lone pair

In general, a lone pair repels bonding electron pairs _____ than bonding pairs repel each other. A lone pair will therefore _____ the bond angle between bonding pairs. A double bond has a similar effect.

more, decrease

Organize the steps for determining molecular shape in the correct order, starting with the first step at the top of the list. Instructions

1. Use the molecular formula to draw a Lewis structure 2. Count the number of electrons 3. Determine the electron-domain geometry by applying the VSEPR model 4. Determine the molecular shape by considering the positions of the atoms only.

The Lewis structure for one of the resonance forms of the sulfate ion, SO42-, is shown. What is the approximate value of the marked O-S-O bond angle? *** tetrahedral pic**

109.5 Reason: Although the structure appears to be flat with right angles between the atoms, the true shape is tetrahedral because there are 4 electron domains. The bond angles are 109.5 degrees .

The Lewis structure for the AsF5 is shown. The approximate value of the bond angle marked "a" is equal to _____ while the approximate value of the bond angle marked "b" is equal to _____. (Remember that this species has a three-dimensional shape, as indicated by the wedged and dashed bonds.) 8trigonal bipyramid

90, 120 Reason: Correct. Recall that the equatorial bonds form a single plane, with 120o angles between them, while the axial bonds are at right angles to the equatorial plane.

Match each ideal bond angle with the correct electron-domain geometry in each case.

90: octahedral 120: trigonal planar 109.5: tetrahedral 180: linear 90 and 120: trigonal bipyramidal 90 degrees, 12o degrees and so on

Select all the statements that correctly describe the five basic electron-domain geometries.

A system with three electron domains will have a trigonal planar electron-domain arrangement. An octahedral geometry indicates that there are six electron domains.

Molecular shapes can be classified using the general designation ABx. Match each symbol in this designation with its correct meaning. Instructions

A: central atom in structure B: terminal atom C: number of terminal atoms

In the molecule KrBr2 there are ____ electron domains surrounding the central Kr atom; ____ bonding pair(s) and ____ lone pair(s). The molecular geometry around the central atom is therefore ____.

Blank 1: 5 or five Blank 2: 2 or two Blank 3: 3 or three Blank 4: linear

In an ABx molecule, the angle between two adjacent A-B bonds is called the ____ angle. This angle is determined by the number of ____ domains or groups surrounding the central atom.

Blank 1: bond Blank 2: electron

The molecular shape of a species, which is the arrangement of the bonded atoms around the central atom, is determined not only by the number of _____ electron domains that join the atoms, but by the number of ____ electron domains as well, since these electrons also occupy space.

Blank 1: bonding, shared, or bonded Blank 2: nonbonding, non-bonding, lone pair, unshared, lone, or unbonded

The electron-domain geometry of a species is the arrangement of electron ___ around the central atom, whereas the molecular geometry is the arrangement of bonded ____. Two species with the same electron-domain geometry may have different molecular geometries.

Blank 1: domains or groups Blank 2: atoms, nuclei, or atomic nuclei

A 5-electron domain system (shown) has two different types of positions for electron domains. The three positions marked "1" form a trigonal plane about the central atom and are called ___ positions, while the two positions marked "2" are ___ positions.

Blank 1: equatorial Blank 2: axial

Molecular shape is determined by the number of electron domains around a central atom, where an electron domain may be a(n) ____ electron pair or any ____ between two atoms.

Blank 1: lone, nonbonded, unbonded, or nonbonding Blank 2: bond or electron pair

Select all the statements that correctly explain why bond angles in molecules containing lone pairs or multiple bonds may be different than the VSEPR ideal.

Lone pairs exert greater repulsion that causes compression in adjacent bond angles. Multiple bonds contain higher electron densities that repel more than single bonds. Multiple bonds repel more strongly than single bonds that results in compression in adjacent bond angles.

Which of the following options correctly describe the structure shown? Select all that apply.

The bond angles around C2 are approximately equal to 180°. C1 will have a tetrahedral geometry. C2 will have a linear geometry.

Match each molecular geometry correctly to the electron-domain arrangement described.

bent: 3 electron domains; 1 lone pair T-shape: 5 electron domains; 2 lone pair square pyramid: 6 electron domains; 1 lone pair tetrahedral: 4 electron domains; 0 lone pairs linear: 2 electron domains; 0 lone pairs

Select all the statements that correctly describe the arrangement of lone pairs in systems with 5 and 6 electron domains.

If there are two lone pairs in an octahedral system they will be located opposite each other. In a trigonal bipyramidal system lone pairs prefer to occupy equatorial positions.

Which of the following options correctly describe the NH2-CH=O structure? Select all that apply.

Nitrogen will have a trigonal pyramidal molecular geometry. Carbon will have a trigonal planar molecular geometry.