* Table is a common noun because it refers to a general category of objects. It's a noun that names any individual piece of furniture with a flat top and one or more legs.
* We can say "a table," "the table," "many tables," and so on.
* Chalk and soap are material nouns because they refer to the substances themselves. They are the names of the materials from which things are made.
* We might say "a piece of chalk," "a bar of soap," "chalk dust," or "soap bubbles."
In summary:
* Common nouns name general things.
* Material nouns name the stuff things are made of.
Let me know if you have any more questions about nouns!