The general electronic configuration of lanthanides can be described like this:
- All lanthanides start after xenon, so they have the xenon core.
- Their electrons are gradually added to the 4f orbitals, from 1 to 14 electrons across the series.
- Some lanthanides may have one electron in the 5d orbital.
- The 6s orbital always has 2 electrons.
For example:
- Lanthanum has electrons in xenon core, one in 5d, and two in 6s.
- Cerium has electrons in xenon core, one in 4f, one in 5d, and two in 6s.
- Neodymium has electrons in xenon core, four in 4f, and two in 6s.
In short, lanthanides gradually fill the 4f orbitals while keeping the 6s electrons stable.