From the data in the table, it is possible to deduce the properties of francium from the trends in the other group 1 metals.
For example, we can predict that francium will have a melting point around 20⁰C and a density of just over 2g/cm³.
We can also predict that francium will react violently with water, producing francium hydroxide and hydrogen.
| Alkali metal | Melting point (⁰C) | Density (g/cm³) | Reaction with water | Products |
|---|---|---|---|---|
| lithium (Li) | 181 | 0.53 | fizzing | lithium hydroxide + hydrogen |
| sodium (Na) | 98 | 0.97 | rapid fizzing | sodium hydroxide + hydrogen |
| potassium (K) | 63 | 0.86 | vigorous fizzing and lilac flame | potassium hydroxide + hydrogen |
| rubidium (Rb) | 39 | 1.53 | ? | rubidium hydroxide + hydrogen |
| caesium(Cs) | 29 | 1.88 | ? | caesium hydroxide + hydrogen |
| francium (Fr) | ? | ? | ? | ? |