Chemical element List of the 118 known chemical elements List of the 118 known chemical elements

| Atomic_no_ | Name_ | Symbol | Group_ | Period | Block | State_at_STP | Occurrence | Description_ |
|---|---|---|---|---|---|---|---|---|
| 55 | Caesium | Cs | 1 | 6 | s | Solid | Primordial | Alkali metal |
| 56 | Barium | Ba | 2 | 6 | s | Solid | Primordial | Alkaline earth metal |
| 57 | Lanthanum | La | 3 | 6 | f | Solid | Primordial | Lanthanide |
| 58 | Cerium | Ce | 3 | 6 | f | Solid | Primordial | Lanthanide |
| 59 | Praseodymium | Pr | 3 | 6 | f | Solid | Primordial | Lanthanide |
| 60 | Neodymium | Nd | 3 | 6 | f | Solid | Primordial | Lanthanide |
| 61 | Promethium | Pm | 3 | 6 | f | Solid | Transient | Lanthanide |
| 62 | Samarium | Sm | 3 | 6 | f | Solid | Primordial | Lanthanide |
| 63 | Europium | Eu | 3 | 6 | f | Solid | Primordial | Lanthanide |
| 64 | Gadolinium | Gd | 3 | 6 | f | Solid | Primordial | Lanthanide |
| 65 | Terbium | Tb | 3 | 6 | f | Solid | Primordial | Lanthanide |