Final answer:
The terms that describe the smallest particle of a substance that retains the chemical properties of that substance are 'atom' and 'molecule'. An atom is the smallest unit of an element, while a molecule is made up of two or more atoms bonded together.
Step-by-step explanation:
The smallest particle of a substance that still retains the chemical properties of that substance is described by two terms: atom and molecule. An atom is the smallest particle of an element that has the properties of that element and can enter into a chemical reaction. On the other hand, a molecule is an electrically neutral group of two or more atoms held together by chemical bonds and is the smallest part of a substance that has the physical and chemical properties of that substance.
To answer the student's question directly, from the options provided, B) molecule and C) atom are the terms that describe the smallest particle of a substance that still retains the chemical properties of that substance.