More Complex Molecular Structures/3D Molecular Structures

Question 1

Line structures

Answer 1

only C-C bonds are shown, element symbols and C-H bonds are omitted

Question 2

What do conjunctions and end points of lines in line structures represent?

Answer 2

Carbon atoms

Question 3

Is formal charge necessary to add to line structures? Why?

Answer 3

Yes because it is needed to account for all electrons since they are not all explicitly shown

Question 4

Isometric structures/isomers

Answer 4

when more than 1 molecular structure corresponds to the same molecular formula

Question 5

What determines if a structure is an isomer?

Answer 5

if they are able to switch between each other at room temperature, they are isomers. if they cannot they are isomers

Question 6

Constitutional isomers

Answer 6

compounds with the same molecular formula but different atomic connectivity

Question 7

What are the characteristics of constitutional isomers?

Answer 7

constitutional isomers can have varying chemical and physical properties

Question 8

Functional group

Answer 8

specific structure that has similar chemical properties whenever it is present in a molecule

Question 9

Moiety

Answer 9

a small group that may reappear in different functional groups

Question 10

Main chain

Answer 10

longest continuous chain of C in a molecule

Question 11

Alkyl group

Answer 11

hydrocarbon branches attached to the main chain

Question 12

Electronegativity

Answer 12

tendency of an atom in a molecule to attract bonding electron density

Question 13

Electronegativity trend

Answer 13

increases left to right, decreases down a group

Question 14

Valence bond theory

Answer 14

a model that focuses on the formation of individual chemical bonds, such as the formation of a sigma bond between 2 atoms within a polyatomic molecule

Question 15

Hybrid orbitals

Answer 15

combinations of valence atomic orbitals that emphasize concentration of electron density in specific directions

Question 16

sp hybridized orbitals

Answer 16

combining the valence s AO with one of the valence p AOs yields 2 degenerate sp hybrid orbitals

Question 17

Geometry of sp orbitals

Answer 17

linear, 180º

Question 18

sp2 hybridized orbitals

Answer 18

combining one valence s AO and 2 valence p AOs produces 3 degenerate sp2 hybrid orbitals

Question 19

Geometry of sp2 orbitals

Answer 19

trigonal planar, 120º; lie closer energetically to the p AO

Question 20

sp3 hybridized orbitals

Answer 20

combining one valence s AO and all 3 valence p AOs produces 4 degenerate sp3 hybridized orbitals

Question 21

Geometry of sp3 orbitals

Answer 21

tetrahedral, 109.5º

Question 22

How does a sigma bond form

Answer 22

one unpaired electron overlaps with a hybrid orbital with one unpaired electron (any type of hybrid orbitals)

Question 23

How does a pi bond form

Answer 23

2 unhybridized p atomic orbitals overlap; above and below the plane of the molecule

Question 24

features of a sigma bond

Answer 24

the most stable bond, orbitals need to change shape, can be rotated around and not broken

Question 25

Wedge-dash notation

Answer 25

straight lines represent bonds in the plane of the page/screen, solid wedges represent bonds coming towards you out of the plane, dashed wedges represent bonds going away from you behind the plane

Question 26

Bent’s rule

Answer 26

a hybrid orbital on a central atom has a greater p character the greater the electronegativity of the other atom forming a bond

Question 27

Hybridization

Answer 27

all hybrid orbitals are around the same nucleus; found in an atom in a molecule, not lone atoms

Question 28

Characteristics of hybridized orbital overlap

Answer 28

Energy decreases, becomes more stable, orbitals will change shape

Question 29

When will a pi bond form?

Answer 29

if there are two unhybridized p orbitals that overlap, cannot form from sp3