When substances combine to form mixtures they keep their properties.
O
True
O
False

True

Explanation:

This is true because When two or more elements or compounds are blended without combining chemically, you've got a mixture. Each substance in a mixture keeps its own properties, and mixtures can be separated using physical or mechanical means. Solids, liquids and gases can all be blended into mixtures.

"the periodic table is arranged in order of atomic number."