Lecture 4 - The Curved Arrow Notaion & Resonance

Question 1

molecules with resonance hybrids or resonance canonical forms are:

Answer 1

resonance-stabilised

Question 2

resonance strucutres help us understand:

Answer 2

molecular structure stability and reactivity

Question 3

what bonds connects two atoms with significantly different electronegativities?

Answer 3

a π-bond (pie)

Question 4

when to draw resonance structures:

Answer 4

1) Two atoms with significantly different electronegativities connected by a π-bond

2) An atom with a lone pair is connected to an electron-deficient atom (lone pair and [+])

3) An electron-deficient atom is next to a π-bond (double bond and [+])

Question 5

how do you know what is the best hybridisation option?

Answer 5

the hybridisation option that maximises an atoms ability to interact most effectively with its neighbour is best

Question 6

describe amides and how their properties are useful in protein structure:

Answer 6

amides are planar and non-basic - this allows proteins to be reasonably stable

Question 7

where are lone pairs the most ‘happy’ on a compound?

Answer 7

lone pairs are the most ‘happy’ when on the most electronegative atom

Question 8

very simplified, described resonance strucutres:

Answer 8

normal lewis strucutres yet with charges on them to better indicate their electron structure and behaviour

Question 9

rules when drawing resonance structures:

Answer 9

1) eight according to energy
2) no change in nuclear positions (only electrons move - not nuclei!)
3) conserve electron spin
4) consider the octet rule (never EXCEED IT - never go above 8 electrons per atom)
5) conserve charge - overall charge must remain the same in all structures