Molecular structure of organic compounds

Question 1

What are the hybrid orbitals and their bond angles?

Answer 1

1s + 3p’s = 4sp’s (109.5°)
1s + 2p’s = 3 sp’s and 1p (120°)
1s + 1p = 2sp’s and 2p’s (180°)

Question 2

Define lewis structures.

Answer 2

Dot and cross diagrams.

Question 3

Define dipole moment.

Answer 3

A measure of charge separation which is the difference in electronegativity of the elements making up a bond.

Question 4

When the dipole moment is larger…

Answer 4

the charge separation/electronegativity difference is larger.

Question 5

What are the ground rules for reaction mechanisms?

Answer 5

Opposites attract, like charges repel. (Exception is spectator ions which dont engage in reaction (Na+, K+ and Ca2+)

Carbon is bonded to the most electronegative atom.

For nucleophiles, the general trend is the stronger the nucleophile, the stronger the base it is.

Question 6

What is the order of nucleophile strength?

Answer 6

RO- > HO-&raquo_space; RCOO-&raquo_space; ROH > H2O

Question 7

When is delocalisation of charges in pi bonds possible?

Answer 7

when there are hybridised orbitals in adjacent atoms

Question 8

What bonds make up a single bond?

Answer 8

a sigma bond

Question 9

What bonds make up a double bond?

Answer 9

a pi bond and a sigma bond

Question 10

What bonds make up a triple bond?

Answer 10

a sigma bond and two pi bonds

Question 11

When does bond energy increase?

Answer 11

with increasing number of bonds

Question 12

When do bond length decrease?

Answer 12

with increasing number of bonds