Smallest particle of a substance that is still identifiable as that substance?
If it is a monatomic substance, then the smallest particle is an atom. If it is not, then the smallest particle would be a molecule of that substance.
What is the the smallest particle of matter still retaining the characteristics of the element building block of matter?
An atom is the smallest indivisible particle of matter. However, some compounds cannot exist as atoms. For example, the smallest particle of Styrofoam retaining the characteristics of Styrofoam is a molecule; atoms are only the smallest retaining the characteristics if the substance in question is an element.
What is the smallest particle of an element that still has the chemical characteristics of that element called?
The smallest particle into which a substance can be divided and still retain all of its chemical properties is?
There are two definitions that can answer particulate identity at its singular unit. If the given is a pure element, the smallest particle retaining identity would be the individual atom (or diatomic molecule in some gases as in O2). If the substance is a molecular compound such as water, its smallest identifying unit would be a single H20 molecule.