Molecule
two or more substances that are together that are together but do not combine to form a new, pure substance
an atom
molecule
Compound
This is not a question or a sentance for that mater. Please restructure. Hydrogen is the smallest pure element. Smallest main structure component of an element is the electron. Hope this helped.
formula unit
The smallest unit of a pure substance that consists of two or more atoms held together by a chemical bond is a molecule.
A chemical compound is a pure chemical substance that consists of two or more different chemical elements which can be separated into simpler substances by a chemical reaction. A molecule is the smallest unit of a compound.
The smallest unit of a pure substance that still has the chemical properties of that substance is called an atom. Atoms can be further broken down into subatomic particles such as protons, neutrons, and electrons.
an atom is the smallest unit of an element, but an element is a pure substance
Two or more atoms joined together; the smallest unit of many substances.
The smallest unit of a substance that has the properties would be either an atom, or more probably a molecule. An atom does not ordinarily exist by itself in nature.