Answer:

1. What happens to the atoms of material that undergo chemical change?

2. How can one tell that materials undergo chemical change?

Explanation:

In a chemical change, the atoms in the reactants rearrange themselves and bond together differently to form one or more new products with different characteristics than the reactants. When a new substance is formed, the change is called a chemical change.

further explaination:

When materials undergo chemical change,the material DON'T retain/remain its shape,size,physical appearance,odor,color or composition.

example:

Burning of wood

Simply,when you burn the WOOD into the fire,it changes it's shape,size and physical appearance into ASHES.