Helium (He). Diagram of the nuclear composition,electron configuration,chemical data,and valence orbitals of an atom of helium-4 (atomic number: 2),the most common isotope of the element helium. The nucleus consists of 2 protons (red) and 2 neutrons (orange). Two electrons (white) fill the first electron shell (ring),a very stable configuration. The stability of an element's outer (valence) electrons determines its chemical and physical properties. Helium is a noble gas in group 18,period 1,and the s-block of the periodic table. At room temperature and pressure it forms an inert gas,liquefying at minus 269 degrees Celsius | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Clarivan, Carlos |
Bildgröße: | 5197 px × 5008 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |