87Fr223.01973
Francium
Alkali Metal
Solid at STP
Period 7Group 1Block SDiscovered 1939
[Rn]7s1
Francium is a chemical element with symbol Fr and atomic number 87. It used to be known as eka-caesium and actinium K. It is the second-least electronegative element, behind only caesium. Francium is a highly radioactive metal that decays into astatine, radium, and radon.
📖 Read more on Wikipedia →Atomic Properties
| Atomic Number | 87 |
| Atomic Mass | 223.01973 u |
| Electron Configuration | [Rn]7s1 |
| Oxidation States | +1 |
| Electronegativity | 0.7 (Pauling) |
| Atomic Radius | 348 pm |
| Ionization Energy | 3.9 eV |
| Electron Affinity | 0.47 eV |
| Block | S |
Physical Properties
| Standard State | Solid |
| Melting Point | 300 K (26.9 °C) |
| CPK Color | #420066 |
Classification
| Category | Alkali Metal |
| Group Block | Alkali metal |
| Period | 7 |
| Group | 1 |
| Block | S |
Discovery
| Year Discovered | 1939 |
| Discovered By | Marguerite Perey |
| Electron Shells | 2, 8, 18, 32, 18, 8, 1 |