| Atom | … |
|---|---|
| An illustration of the helium atom, depicting the nucleus (pink) and the electron cloud distribution (black). The nucleus (upper right) in helium-4 is in reality spherically symmetric and closely resembles the electron cloud, although for more complicated nuclei this is not always the case. The black bar is one angstrom (10 m or 100 pm). | … |
| Classification | … |
| Smallest recognized division of a chemical element | … |
| Properties | … |
| Mass range | 1.67×10 to 4.52×10 kg |
| Electric charge | zero (neutral), or ion charge |
| Diameter range | 62 pm (He) to 520 pm (Cs) (data page) |
| Components | Electrons and a compact nucleus of protons and neutrons |
(echo:: @ ᯤ)