This is the atom.
Molecule
The smallest particle of a substance that still retains all the chemical properties of that substance is called a molecule. In the case of elements, the smallest particle is an atom, which retains the unique properties of that element. Molecules are made up of atoms bonded together in specific arrangements that determine the chemical behavior of the substance. Therefore, the smallest particle of a substance that is still that substance does indeed possess all the properties of that substance.
For an element, it would be an atom. For a molecular substance, it would be a molecule. If it is an ionic compound, it would be a formula unit.
atoms
Molecule
It is a molecule of the substance.
The smallest particle of a substance that retains all the properties of the substance and is composed of one or more atoms is called a molecule. Each molecule is made up of one or more atoms chemically bonded together.
Particle theory explains that all matter is made up of tiny particles. In the case of pure substances, these particles are the same throughout the substance, giving it a uniform composition. This understanding helps in identifying and describing the properties of pure substances based on the behavior of their particles.
Element
Physical :)
The smallest particle of a substance that retains all properties is an atom. An atom is composed of a nucleus containing protons and neutrons, surrounded by electrons. In some cases, atoms can combine to form molecules, but the individual atom remains the smallest unit that retains the substance's properties.
A pure substance is a material that has a constant chemical composition and properties. It is made up of only one type of particle, such as an element or a compound, and cannot be separated into simpler substances by physical means. Examples of pure substances include water (H2O) and gold (Au).