Fr
Alkali metal
Francium
Z 87A 223mass 223
Atomic model
tap a particleEvery nucleon is drawn individually — 87 protons and 136 neutrons packed into the nucleus, with 87 electrons on shells outside.
87+1
Protons
Set the element — change this and it becomes a different atom.
1360
Neutrons
Change only these and you get a different isotope of the same element.
87−1
Electrons
Sit outside the nucleus and decide the chemistry, not the element.
Element data
- Nucleons
- 223 (87 p + 136 n)
- Electron shells
- 2 · 8 · 18 · 32 · 18 · 8 · 1
- Valence shell
- 1 electrons
- Atomic mass
- 223 u
Stability
Francium has no measured radioactive isotope in this lab — its nuclei are stable, so decay must be shown as an illustration.
Open the decay lab