I
Halogen
Iodine
Z 53A 127mass 126.9
Atomic model
tap a particleEvery nucleon is drawn individually — 53 protons and 74 neutrons packed into the nucleus, with 53 electrons on shells outside.
53+1
Protons
Set the element — change this and it becomes a different atom.
740
Neutrons
Change only these and you get a different isotope of the same element.
53−1
Electrons
Sit outside the nucleus and decide the chemistry, not the element.
Element data
- Nucleons
- 127 (53 p + 74 n)
- Electron shells
- 2 · 8 · 18 · 18 · 7
- Valence shell
- 7 electrons
- Atomic mass
- 126.9 u