53I126.9
Iodine
Halogen · element 53 · group 17, period 5
Quick facts
| Symbol | I |
|---|---|
| Atomic number | 53 |
| Relative atomic mass | 126.9 |
| Category | Halogen |
| Position | group 17, period 5 |
| State at 20 °C | Solid |
| Melting point | 113.7 °C |
| Boiling point | 184.3 °C |
| Density | 4.933 g/cm³ |
| Electronegativity | 2.66 |
| Electron configuration | [Kr] 4d10 5s2 5p5 |
About Iodine
Iodine has the symbol I and atomic number 53, which means every iodine atom has 53 protons in its nucleus and, in a neutral atom, 53 electrons. At room temperature it is a solid.
Halogens are in group 7. They have 7 outer electrons, exist as diatomic molecules (like Cl₂), and get less reactive going down the group.
It melts at 113.7 °C and boils at 184.3 °C.
Explore it
See where iodine sits, and drag the temperature slider to watch it melt and boil, on the interactive periodic table. Practise with quizzes on OmniEx.