Deck 1: Atomic and Molecular Structure

Question 1

An atom of which element would have an electron configuration of 1s²2s²2p⁶3s²3p¹?

A)Al
B)Ne
C)B
D)Si
E)Na

Answer 1

Al

Question 2

Identify which carbon atom in the molecule below is most oxidized.

A)I
B)II
C)III
D)IV
E)V

Answer 2

V

Question 3

Which electron configuration is correct for the carbon of a carbocation?

A)1s²2s²2p¹
B)1s²2s²2p³
C)1s²2s²2p⁵
D)1s²2s²2p⁶3s²3p⁵
E)1s²2s²2p⁴

Answer 3

1s²2s²2p¹

Question 4

Which of the following is an example of an electrostatic attractive force between particles at the atomic level?

A)Neutrons attract protons.
B)Protons repel protons.
C)Core electrons attract valence electrons.
D)Protons attract electrons.
E)Electrons attract neutrons.

Question 5

Which point on the following diagram can be extrapolated to identify the length and strength of a chemical bond?

A)A
B)B
C)C
D)D
E)E

Question 6

A C-O single bond is 143 pm in length,whereas an O-O single bond is 148 pm in length. Which bond is weaker and why?

A)The C-O bond is weaker because O is more electronegative than C.
B)The C-O bond is weaker because each O atom is electronegative and pulls the shared electrons toward itself.
C)The O-O bond is weaker because oxygen has d orbitals to engage in bonding.
D)The C-O bond is weaker because C is more electronegative than O.
E)The O-O bond is weaker because both oxygens are equally electronegative and pull the shared electrons toward themselves.

Question 7

Identify which carbon atom in the molecule below is most reduced.

A)I
B)II
C)III
D)IV
E)V

Question 8

Which line structure is correct for Molecule Z?

A)I
B)II
C)III
D)IV
E)V

Question 9

Consider the interesting structure below,called a dibromocarbene.The carbon of the dibromocarbene has one lone electron pair and two separate covalent bonds to individual bromine atoms.What is the formal charge on the carbon atom of the dibromocarbene?

A)+2
B)+1
C)0
D)-1
E)-2

Question 10

Which electron configuration is correct for a carbon atom with a formal charge of -1?

A)1s²2s²2p⁶3s¹
B)1s²2s²2p³
C)1s²2s²2p⁵
D)1s²2s²2p⁶3s²3p⁵
E)1s²2s²2p⁴

Question 11

Evaluate the Lewis structure below and determine its legitimacy.

A)The structure is legitimate.
B)The structure is not legitimate, because the oxygen does not have an octet.
C)The structure is not legitimate, because the formal charges are not shown.
D)The structure is not legitimate, because the middle carbon lacks an octet.
E)The structure is not legitimate, because the leftmost carbon is missing a lone pair.

Question 12

Which orbital does not house core electrons for a bromine atom?

A)1s
B)4p
C)3p
D)2s
E)3s

Question 13

Which point on the following diagram represents two atoms functioning independently?
)

A)A
B)B
C)C
D)D
E)E

Question 14

When two Lewis structures are related as resonance forms,which of the following are true?
I. When compared,the resonance forms have the same atoms connected in the same order.
II. Either individual Lewis structure can be used as an accurate representation of valence electron distribution.
III.Electrons in single bonds may be delocalized in the resonance forms.
IV.Electrons in a multiple bond may be delocalized in the resonance forms.
V. A lone pair of electrons on an atom adjacent to a multiple bond can be delocalized in the resonance forms.

A)All are true.
B)Only I, II, IV, and V are true.
C)Only I, III, IV, and V are true.
D)Only I, IV, and V are true.
E)Only I and IV are true.

Question 15

What is the molecular formula of this compound?

A)C₆H₁₂NO₂
B)C₅H₁₂NO₂
C)C₅H₁₁NO₂
D)C₆H₁₁NO₂
E)C₆H₁₃NO₂

Question 16

Which carbon atom has an oxidation state of +3?

A)I
B)II
C)III
D)IV
E)V

Question 17

Which electron configuration is correct for a Ca²⁺ ion?

A)1s²2s²2p⁶3s²3p¹
B)1s²2s²2p⁶3s²3p⁶4s²
C)1s²2s²2p⁶3s²3p⁶
D)1s²2s²2p⁶3s²3p⁶4s²4p⁶
E)1s²2s²2p⁶3s²

Question 18

How many valence electrons are assigned to oxygen when determining formal charge in the ionic compound sodium methoxide,NaOCH₃?

A)4
B)5
C)6
D)7
E)8

Question 19

Which of the following Lewis structures violates the octet rule and is therefore incorrect?

A)Structure I
B)Structure II
C)Structure III
D)Structure IV
E)Structure V

Question 20

How many total valence electrons are used in the structure of ammonium chloride,NH₄Cl?

A)13
B)14
C)15
D)16
E)28

Question 21

Which condensed formula contains an ester?

A)(CH₃CH₂)2O
B)CH₃CO₂CH₂CH₃
C)CH₃CH₂CH₂COOH
D)CH₃CH₂OH
E)CH₃COH

Question 22

A compound with a molecular formula of C₇H₇Br has a melting point of 203°C.The compound is soluble in water but not in diethyl ether.Based on your knowledge of organic structure,is the compound most stable in its ionic or covalent form? Justify your answer.

Question 23

Which condensed formula contains a carboxylic acid?

A)CH₃COCH₃
B)CH₃CO₂CH₂CH₃
C)CH₃CH₂CH₂COOH
D)CH₃CH₂OH
E)CH₃COH

Question 24

Compare Structure A with Structures B,C,and D.Is Structure B,C,or D a resonance structure of A? Justify your response.For any structures that are resonance forms,use curved arrows to show how the resonance forms are interconverted.

Question 25

Predict which carbon atom should have the greatest negative charge density.Explain your answer.What would the electrostatic potential map show for this carbon,in comparison with others in the molecule?

Question 26

Which of the following $\alpha$ amino acids possesses two hydrogen atoms adjacent to the carboxylic acid?

A)Serine
B)Phenylalanine
C)Glycine
D)Tryptophan
E)Lysine

Question 27

Using a chemical reaction to convert an alcohol to an oxonium species is a highly valued tool in every organic chemist's arsenal (see the figure below).Although this reaction was not covered in the current chapter,it will be discussed in due course.Reconsider your response to the preceding question.Can you identify the two different atoms of the oxonium species to which a negatively charged species might be most attracted? Explain.Hint: It is not the oxygen with the positive charge.

Question 28

Consider two solvents that are commonly used for organic chemistry reactions: CH₂Cl₂ and CCl₄.Interestingly,studies have shown that one of these solvents is polar and one is nonpolar.Draw valid Lewis structures for these two molecules.Show bond dipoles and both partial charges (use δ+ and δ-).How would the electrostatic potential maps for the two molecules be similar? How would they be different?

Question 29

Which condensed formula contains a ketone?

A)CH₃COCH₃
B)CH₃CO₂CH₂CH₃
C)CH₃CH₂CH₂COOH
D)CH₃CH₂OH
E)CH₃COH

Question 30

Which individual structures below could be contributing resonance structures to the given hybrid structure?

A)All are contributing structures.
B)All but V are contributing structures.
C)I, II, and III are contributing structures.
D)I, III, and IV are contributing structures.
E)Only I and III are contributing structures.

Question 31

Which would you expect to be a stronger bond: C-Si or C-C?

Question 32

Using line structures,deduce individual resonance contributors from the resonance hybrid structure given here.

Question 33

Oxygen is an important heteroatom found in many organic molecules.Consider methanol and its protonated derivative,shown below.Indicate relevant bond dipoles using dipole arrows.How does an oxygen with a positive charge,called an oxonium species,influence the magnitude of the partial positive charge on the carbon atom? Which oxygen-carbon bond do you think is more difficult to break? Explain.

Question 34

Using line structures,draw the individual resonance contributors from the resonance hybrid structure given here.

Question 35

Draw a Lewis structure of thionyl chloride,SOCl₂,showing all lone pairs.Show each bond dipole using a dipole arrow.

Question 36

Naltrexone is an FDA-approved treatment for alcoholism that targets the mu opioid receptor.Name four functional groups that are present in naltrexone.

A)Amine, phenol, aldehyde, ether
B)Amine, phenol, amide, alcohol
C)Amine, phenol, ketone, alcohol
D)Ether, ketone, amide, alcohol
E)Ketone, phenol, alcohol, ester

Question 37

For which of the following $\alpha$ amino acids can resonance forms be drawn for its side chain?

A)Alanine
B)Methionine
C)Glycine
D)Proline
E)Histidine

Question 38

Which condensed formula contains an aldehyde functional group?

A)CH₃COCH₃
B)CH₃CO₂CH₂CH₃
C)CH₃CH₂CH₂COOH
D)CH₃CH₂OH
E)CH₃COH

Question 39

The evolution of a chemical bond can be tracked by plotting energy versus internuclear distance,as shown in the figure here.Describe what is occurring at the atomic level for points A-E on the graph.

Question 40

In sum,how many total hydrogen atoms are directly connected to the phenyl rings found in the molecule below?

A)8
B)9
C)10
D)11
E)12

Question 41

Identify the molecules below as monosaccharides,disaccharides,or carbohydrates.Explain the distinction between these classes of biologically active organic molecules.

Question 42

A carbonyl,the C
O unit,is a component of many important functional groups.Consider the Lewis structures below.Convert the Lewis structures to line structures,showing all lone pairs.Indicate bond dipoles using the arrow method.Rank the structures for increasing partial positive charge.Predict which carbonyl carbon should have greatest partial positive charge,assuming that the chlorine lone pairs do not engage in resonance.Explain your answer.

Question 43

Are the Lewis structures for sulfuric acid shown below related as resonance structures? Explain.

Question 44

(a)Sulfuric acid,H₂SO₄,is an important strong oxo acid in organic chemistry.Propose Lewis structures for sulfuric acid,showing all lone pairs and formal charges,using the following guidelines:
In Structure I,one atom has a +2 formal charge.Two other atoms each possess a charge of -1.All atoms in Structure II are completely neutral.In Structure III,one atom has a +1 charge and another a -1 charge.
(b)Which Lewis structure is most stable? Why?
The neutral structure is most stable.The number of covalent bonds is maximized,and charges are minimized (e.g.,there are no individual formal charges on atoms).

Question 45

Draw all possible resonance forms for anisole using appropriate arrow notation.Which resonance structure is most stable? Least stable? Draw the resonance hybrid for anisole,indicating all partial charges.

Question 46

The six unique hydrogen atoms in the molecule below are labeled a-f.Suppose we individually replace each of these unique hydrogen atoms with a hydroxyl group (-OH)and draw a new molecule of formula C₆H₁₀O₂.(In the cases of H_a,H_b,and H_c,substitute only one designated H with an OH.)Which of the new -OH groups would have localized lone pairs on oxygen? Which of the -OH groups would have a delocalized lone pair? Finally,for each molecule,identify the new functional group created.

Question 47

Global warming and ozone depletion both have far reaching environmental consequences and are linked by human cause.Propose two reasonable structures of ozone,O₃,that differ in electron delocalization and do not contain a ring.Show how these two structures are interconverted using appropriate arrow notation.Explain the relationship between these molecules.

Question 48

Consider a peptide bond formed from the amino acids alanine and serine.Redraw the dipeptide from the figure below using a line structure.Once this structure is drawn,place a box around the amide bond.Circle the parts of the dipeptide that originate from serine and alanine.

Question 49

To which carbon atoms in anisole would a positively charged species,called "E⁺," bond? Explain your answer using the concept of resonance.HINT: Refer to your response from 16 for further insight.

Question 50

Peptide bonds are the building blocks of proteins.Consider a peptide bond formed from the amino acids alanine and serine,shown below.Draw the resonance forms and the resonance hybrid for the amide bond of the dipeptide.Use appropriate arrow notation.

Question 51

Identify the functional groups present in the structure of the dipeptide shown below.In your answer,do not use "alkane."

Question 52

Amino acids are important building blocks in chemistry.Consider the structure below,which can be formed from reaction of an $\alpha$ amino acid with another compound.Identify the $\alpha$ amino acid that is used in the synthesis.Clearly label the amino acid side chain,the alpha carbon,the amine,and the carboxylic acid within the larger structure.What parts of the larger molecule do not come from the amino acid?

Question 53

The way atoms are connected to each other in an organic structure determines the chemical behavior of the structure.Using line structures,propose individual molecules with the formula C₄H₈O that contain the following functional groups:
(a)A ketone (e)A cyclic ether that is not an epoxide
(b)An aldehyde with a branched alkane (f)An epoxide
(c)An aldehyde with an unbranched alkane (g)An acyclic ether
(d)A cycloalkane (h)An alkene and an alcohol

Question 54

Tubulysin D is a potent cytotoxic compound that interferes with mitosis.Identify the following structural features of Tubulysin D.
(a)Place a box around any amide found in the molecule.
(b)Circle the phenyl group(s).
(c)Place a triangle around the carboxylic acid(s).
(d)Star any carbon atoms with a -3 oxidation state.