For example hydrogen has the atomic number of one, helium two, lithium three etc. The first energy level (the one nearest the nucleus) can hold a maximum of 2 electrons with the others being able ...

Precision spectroscopy of helium and other atomic systems is ... which affects the hyperfine structure of atomic energy levels. This Nature Research Intelligence Topic summary is one of 30,000 ...

National Periodic Table Day, observed annually on February 7, honors one of the most significant achievements in scientific ...