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|