Cs
Alkali metal
Cesium
Z 55A 133mass 132.91
Atomic model
tap a particleEvery nucleon is drawn individually — 55 protons and 78 neutrons packed into the nucleus, with 55 electrons on shells outside.
55+1
Protons
Set the element — change this and it becomes a different atom.
780
Neutrons
Change only these and you get a different isotope of the same element.
55−1
Electrons
Sit outside the nucleus and decide the chemistry, not the element.
Element data
- Nucleons
- 133 (55 p + 78 n)
- Electron shells
- 2 · 8 · 18 · 18 · 8 · 1
- Valence shell
- 1 electrons
- Atomic mass
- 132.91 u