The size of an electron is significantly smaller compared to an atom or molecule. Electrons are elementary particles and are considered point-like particles, meaning they are thought to have no size or spatial extent. In other words, electrons are considered to be fundamental particles with no measurable dimensions.
On the other hand, atoms and molecules have a size and spatial extent. Atoms consist of a central nucleus, which contains protons and neutrons, surrounded by one or more electrons occupying specific energy levels or orbitals. The size of an atom is typically measured by its atomic radius, which is the distance from the nucleus to the outermost electron orbital.
The atomic radius varies depending on the specific element and its electronic configuration. For example, the atomic radius of a hydrogen atom is about 52.9 picometers (pm), while the atomic radius of a helium atom is about 31 pm.
Molecules, which are formed by the combination of atoms, can have larger sizes depending on the arrangement of atoms within the molecule. The size of a molecule is typically measured by its bond lengths or interatomic distances, which represent the distances between the atomic nuclei within the molecule.
In summary, electrons are much smaller compared to atoms and molecules. While atoms and molecules have measurable sizes and dimensions, electrons are considered point-like particles with no measurable spatial extent.