Iodine (I)
Iodine (I, element 53) is a halogen in group 17, period 5. Atomic mass 126.904, electron configuration [Kr] 4d¹⁰ 5s² 5p⁵, uses and facts.
About Iodine
Iodine is a halogen with the symbol I and atomic number 53. It is a solid at room temperature, and it sits in group 17, period 5 of the periodic table. Iodine was discovered in 1811 by Bernard Courtois.
Iodine key facts
- Atomic number: 53
- Symbol: I
- Atomic mass: 126.904 u
- Category: halogen
- Group: 17
- Period: 5
- State at room temperature: solid
- Electron configuration: [Kr] 4d¹⁰ 5s² 5p⁵
- Electronegativity (Pauling): 2.66
- Melting point: 386.85 K (113.7 °C)
- Boiling point: 457.4 K (184.25 °C)
- Density: 4.933 g/cm³
- Common oxidation states: −1, 0, +1, +3, +5, +7
Electron configuration
The electron configuration of iodine is [Kr] 4d¹⁰ 5s² 5p⁵. The part in brackets is the noble gas core; the rest shows how the outer electrons fill their subshells. Iodine has 7 valence electrons.
Uses of iodine
- Antiseptic
- Thyroid medication
- Photography
Did you know?
Your thyroid gland needs iodine to function. Without it, the gland swells into a goiter.
Other elements in group 17 and neighbours
Frequently asked questions
What is the atomic number of iodine?
The atomic number of iodine is 53, which means every iodine atom has 53 protons.
What is the electron configuration of iodine?
The electron configuration of iodine is [Kr] 4d¹⁰ 5s² 5p⁵.
What group and period is iodine in?
Iodine is a halogen in group 17, period 5.
What state is iodine at room temperature?
Iodine is a solid at room temperature.
What is iodine used for?
Iodine is used for antiseptic, thyroid medication, photography.