Be
Alkaline earth metal
Beryllium
Z 4A 9mass 9.012
Atomic model
tap a particleEvery nucleon is drawn individually — 4 protons and 5 neutrons packed into the nucleus, with 4 electrons on shells outside.
4+1
Protons
Set the element — change this and it becomes a different atom.
50
Neutrons
Change only these and you get a different isotope of the same element.
4−1
Electrons
Sit outside the nucleus and decide the chemistry, not the element.
Element data
- Nucleons
- 9 (4 p + 5 n)
- Electron shells
- 2 · 2
- Valence shell
- 2 electrons
- Atomic mass
- 9.012 u
Stability
Beryllium has no measured radioactive isotope in this lab — its nuclei are stable, so decay must be shown as an illustration.
Open the decay lab