Francium is an extremely rare radioactive metal.
Uses and research
Its short-lived isotopes make bulk studies difficult.
A family of reactive metals
Alkali metals occupy group 1, apart from hydrogen, which is not an alkali metal. The metals react readily and occur naturally in compounds. An element in a mineral or salt is not the same substance as a piece of its pure metal. Distinguishing the substance from the element is a useful first step.
What the atomic number tells us
Francium has atomic number 87. This is the number of protons in its nucleus. A neutral atom also has 87 electrons. Losing or gaining electrons makes an ion; it does not change the element unless the proton count changes.
The model's rings help count electrons by shell. They are not actual circular paths. A model of one atom and the properties of a whole material are different levels of description.
Temperature and state
25°C: Data not included
Illustrative particle motion: sizes, distances and speeds are not to scale. Particles represent atoms or molecules.
← CoolHeat →
Temperature data is not included in this guide.
Pure element at 1 atmosphere. Image conditions are explained in captions. Pictures do not change with temperature.