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Question 1

Relation to Basicity:
The weaker the base, the better the leaving group.

Answer 1

A weak base can stabilize the negative charge more effectively after departing.

Question 2

Periodic Trends:

Answer 2

Across a Period (Row):
Basicity decreases from left to right across a row of the periodic table.
Leaving group ability increases from left to right.
Example:
N
H
3
NH
3
​
(weaker leaving group) vs.
H
2
O
H
2
​
O (better leaving group).

Question 3

Down a Group (Column):

Answer 3

Basicity decreases as you move down the group in the periodic table.
Leaving group ability increases as you move down the group.
Example:
F
−
<
C
l
−
<
B
r
−
<
I
−
F
−
<Cl
−
<Br
−
<I
−
(increasing leaving group ability).

Question 4

Question: Why is
H
2
O
H
2
​
O a better leaving group than
N
H
3
NH
3
​
?

Answer 4

Answer:
H
2
O
H
2
​
O is a weaker base and more stable after departure, making it a better leaving group.

Question 5

How does leaving group ability change across a period of the periodic table?

Answer 5

Answer: It increases from left to right because basicity decreases.

Question 6

Which is a better leaving group:
C
l
−
Cl
−
or
I
−
I
−
?

Answer 6

Answer:
I
−
I
−
is a better leaving group because it is a weaker base and more stable.

Question 7

Arrange the following in order of increasing leaving group ability:
F
−
F
−
,
I
−
I
−
,
C
l
−
Cl
−
,
B
r
−
Br
−
.

Answer 7

Answer:
F
−
<
C
l
−
<
B
r
−
<
I
−
F
−
<Cl
−
<Br
−
<I
−
.

Question 8

What is the general rule for determining a good leaving group?

Answer 8

Answer: The weaker the base, the better the leaving group.

Question 9

Why does basicity decrease down a group in the periodic table?

Answer 9

Answer: Because larger atoms can better stabilize the negative charge due to their size and lower charge density.