Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

AH Chemistry > 3.1 - Molecular orbitals > Flashcards

3.1 - Molecular orbitals Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

what are formed when atomic orbitals combine

A

molecular orbitals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how many molecular orbitals are formed from two atomic orbitals combining?

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the 2 types of molecular orbital formed from the combination of 2 atomic orbitals

A

a bonding and an antibonding orbital

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

which molecular orbital encompasses both nuclei

A

the bonding orbital

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the basis of bonding between atoms

A

the attraction of the positively charged nuclei and the negatively charged electrons, in the bonding orbital.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how many electrons can a molecular orbital hold?

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

describe how the bonding orbital looks in a non-polar covalent bond

A

symmetrical about the

midpoint between two atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

describe how the bonding orbital looks in a polar covalent bond

A

asymmetric about the midpoint between two atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

describe how the bonding orbital looks in an ionic bond

A

the bonding molecular orbitals being almost entirely located around just one atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is a sigma bond

A

a molecular orbital formed by end-on overlap of atomic orbitals along the axis of the covalent bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is a pi bond

A

a molecular orbital formed by side-on overlap of parallel atomic orbitals that lie perpendicular to the axis of the covalent bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

explain the process of hybridisation

A

mixing atomic orbitals within an atom to generate a set of new atomic orbitals called hybrid orbitals.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

are hybrid orbitals degenerate

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the 3 hybrid orbitals that carbon can form

A

(4) sp³, (3) sp² and (2) sp orbitals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what spatial arrangement do sp³ orbitals form

A

tetrahedral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what spatial arrangement do sp² orbitals form

A

trigonal planar

17
Q

what type of bonds do carbon hybrid orbitals form with other atomic orbitals

A

sigma bonds

18
Q

in a carbon carbon double or triple bonds, what type of bond do the unhybridised orbitals form

A

pi bonds

19
Q

what is the chemical formula for benzene

A

C₆H₆

20
Q

how is a a ring of delocalised electrons formed in benzene

A

the unhybridised p orbitals on each carbon atom overlap side-on forming a pi molecular system, between all six carbon atoms.

21
Q

what is the name for hydrocarbons containing a carbon-carbon triple bond

A

alkynes

22
Q

what does HOMO stand for

A

highest occupied molecular orbital

23
Q

what does LUMO stand for

A

lowest unoccupied molecular orbital

24
Q

is the HOMO a bonding or antibonding orbital

A

bonding

25
Q

do electrons usually fill bonding, or antibonding orbitals

A

bonding

26
Q

what causes electrons to be promoted from HOMO to LUMO

A

absorption of electromagnetic radiation

27
Q

why do most organic molecules appear colourless

A

the energy difference between HOMO and LUMO is relatively large, causing radiation emitted to be in the UV spectrum

28
Q

what is a chromophore

A

the region of a molecule which determines its colour

29
Q

chromophores exist in molecules containing what

A

a conjugated system

30
Q

what is a conjugated system

A

a system of adjacent unhybridised p orbitals that overlap side-on to form a molecular orbital across a number of carbon atoms. electrons are delocalised.

31
Q

which molecules have a conjugate system

A

molecules with alternating single and double bonds, and aromatic molecules

32
Q

what decreases the energy gap between HOMO and LUMO

A

the more atoms in the conjugated system

33
Q

when does a compound appear coloured

A

when the wavelength of light absorbed is in the visible region (the compound will exhibit the complementary colour)

AH Chemistry (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions