Deck 5: Polyatomic Molecules

Question 1

The 'formal charge' is defined as?

A) The number of valence electrons for an atom.
B) The difference between valence electrons in the free atom and the number of atoms assigned to that atom in its Lewis structure.
C) The highest oxidation state expected in a particular group.
D) The most common oxidation state of a particular atom.

Answer 1

B

Question 2

In the second period from Li to Ne, while no molecules exist which have more than eight electrons, there are some which exist with less. These molecules are described as electron ____

Answer 2

poor

Question 3

COS adopts a structure with a central carbon atom.

Answer 3

True

Question 4

When negative charges are present in a structure where formal charges can be assigned, the lowest energy structure is the one with the negative charge on the most ____________ atom.

Question 5

Which of the following factors affect the shape at the central atom in VSEPR theory? Please select all that apply.

A) The charge.
B) The  bonded electron pairs.
C) The  bonded electron pairs.
D) The electronic contribution of the ligands.

Question 6

When predicting the shape of a molecule containing lone pairs, which of the following should be arranged first?

A) lone pairs
B) double bonds
C) single bonds
D) triple bonds

Question 7

Which of the following geometries are predicted for molecules in which all the electron pairs are bonding in VSEPR theory? Please select all that apply.

A) linear
B) tetrahedral
C) square pyramidal
D) pentagonal bipyramidal

Question 8

In VSEPR theory, the most important interactions that should be considered when placing bonding and lone pairs of electrons in a trigonal bipyramid occur at 90°.

Question 9

Use VSEPR theory to match the molecule with its shape.
-[ClF₄]^-

A) square planar
B) angular
C) pyramidal
D) tetrahedral

Question 10

Use VSEPR theory to match the molecule with its shape.
-H₂S

A) square planar
B) angular
C) pyramidal
D) tetrahedral

Question 11

Use VSEPR theory to match the molecule with its shape.
-PH₃

A) square planar
B) angular
C) pyramidal
D) tetrahedral

Question 12

Use VSEPR theory to match the molecule with its shape.
-CCl₂(CH₃)₂

A) square planar
B) angular
C) pyramidal
D) tetrahedral

Question 13

The shape predicted by VSEPR theory for [BrF₄]⁺ is trigonal pyramidal.

Question 14

Using VSEPR theory, a molecule having 5 electron pairs divided between 3 bonding pairs and 2 lone pairs will be trigonal planar true-false

Question 15

A double bond takes up less room than a single bond. true-false

Question 16

Use VSEPR theory to determine the structure of the borate anion, [BO₄]^5-.

A) Trigonal bipyramidal with one lone pair and four bond pairs.
B) Trigonal bipyramidal with two lone pairs and three bond pairs.
C) Tetrahedral
D) Square planar

Question 17

VSEPR predicts that shape of the ion TeBr₆^2- is octahedral.

Question 18

The linear molecule COS is non polar.

Question 19

A stream of trichloromethane (chloroform) will be deflected by a positive charge because the more electronegative ____ atoms generate dipoles which do not cancel each other out.

Question 20

The process of an atom changing the energy and shape of its atomic orbitals to increase the opportunities for bonding with other atoms is called __________

Question 21

BeMe₂ rapidly polymerizes to form a linear chain of tetrahedral Be atoms. The same process does not occur for BeBu^t₂ due to steric hindrance and the shape at Be is linear. What sort of hybridization is present in each case?

A) BeMe₂ is sp² hybridized and BeBu^t₂ is sp hybridized.
B) BeMe₂is sp³ hybridized and BeBu^t₂ is sp hybridized.
C) BeMe₂is sp³ hybridized and BeBu^t₂ is sp² hybridized.
D) BeMe₂is sp hybridized and BeBu^t₂ is sp³ hybridized.

Question 22

For each of the atoms highlighted in bold, determine the type of hybridization present.
-CH₃CH₂CCH

A) sp
B) sp²
C) sp³

Question 23

For each of the atoms highlighted in bold, determine the type of hybridization present.
-C₆H₅CO₂H (benzoic acid)

A) sp
B) sp²
C) sp³

Question 24

For each of the atoms highlighted in bold, determine the type of hybridization present.
-CH₃CH₂OH

A) sp
B) sp²
C) sp³

Question 25

SF₆ is a hypervalent compound of sulfur which lies in the third period of the Periodic Table. Charge separation can be use to account for the exceptional valence of SF₆.

Question 26

In the BeH₂ molecular orbital diagram shown below, the Be is double bonded to the H atoms.

Question 27

In BeH₂, the 2_g orbital is closer in energy and properties to the atomic orbitals of _______

Question 28

The total number of electrons surrounding Xe in XeF₄ as predicted by VSEPR theory is 12. Valence bond theory would suggest that this arrangement would require d²sp³ hybridization.

Question 29

One way of describing the bonding in XeF₂ which avoids hypervalency for xenon is using the 3 centre 4 electron bond. Which combination of orbitals generate a non-bonding combination for the XeF₂ molecule?

A) In phase combination of the two F p_z orbitals and the p_z orbital on the Xe.
B) Out of phase combination of the two F p_z orbitals and the p_z orbital on the Xe.
C) In phase combination of the two F p_z orbitals and the p_x orbital on the Xe.
D) In phase combination of the two F p_x orbitals and the p_z orbital on the Xe.

Question 30

The bonding in B₂H₆ is best described by which of the following statements?

A) 2-centre 2-electron bonds, 3-centre 2-electron bonding and 2-centre 2-electron bonding
B) 3-centre 2-electron bonding and 2-centre 2-electron bonding
C) 3-centre 4-electron bonds
D) 3-centre 2-electron bonding