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Compare Fluorine vs Iodine

Comparing Fluorine (F) and Iodine (I). Atomic numbers 9 and 53 with atomic masses 18.998 u and 126.904 u, classified as nonmetal and nonmetal. Below: a side-by-side comparison of their physical, atomic, electron-configuration and historical properties, including density, melting and boiling points, ionization energies, oxidation states and discovery history.

vs
F
Fluorine
#9
I
Iodine
#53

Periodic properties of the elements

FluorineIodine
SymbolFI
Atomic number953
Group1717
Period25
Blockpp
Element categoryNonmetalNonmetal

Physical properties

FluorineIodine
Phase at STPGasSolid
Density1.696 g/cm34.933 g/cm3
Atomic weight18.9984 u126.904 u
Melting point53.48 K
-219.67 °C
-363.406 °F		386.85 K
113.7 °C
236.66 °F
Boiling point85.03 K
-188.12 °C
-306.616 °F		457.4 K
184.25 °C
363.65 °F

Atomic properties

FluorineIodine
Electronegativity (Pauling Scale)3.982.66
Electron affinity328.165 kJ/mol295.153 kJ/mol
Oxidation states−1, 0
(oxidizes oxygen)		−1, +1, +3, +4, +5, +6, +7
(a strongly acidic oxide)
Ionization energies
  1. 1681 kJ/mol
  2. 3374.2 kJ/mol
  3. 6050.4 kJ/mol
  4. 8407.7 kJ/mol
  5. 11022.7 kJ/mol
  6. 15164.1 kJ/mol
  7. 17868 kJ/mol
  8. 92038.1 kJ/mol
  9. 106434.3 kJ/mol
  1. 1008.4 kJ/mol
  2. 1845.9 kJ/mol
  3. 3180 kJ/mol

Electron configuration

FluorineIodine
Shorthand configuration[He] 2s2 2p5 [Kr] 4d10 5s2 5p5
Full configuration1s2 2s2 2p5 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p5
Electrons per shell2, 72, 8, 18, 18, 7

History

FluorineIodine
DiscoveryAndré-Marie Ampère (1810)Bernard Courtois (1811)
First isolationHenri Moissan (1886)Bernard Courtois (1811)
Named byHumphry Davy, André-Marie AmpèreJoseph Louis Gay-Lussac (1813)
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