FOUR RHYMING RIDDLES

1)
I know a word of letters three;
Add one more and none there will be.

2)
You may envy me if you want to snoop,
But you'll complain if I'm in your soup.

3)
On the chart I remain number one,
And my position will never be undone.

4)
I am one, though worth a thousand,
Holding memories both bitter and sweet;
Of yesterday, today, or long ago,
A moment in time is what I show.

Answers:

1. ONE (NONE)
2. a fly (on the wall)
3. hydrogen (on the Periodic Table)
4. a picture (is worth a thousand words)