A-level Chemistry/OCR (Salters)/Halogens
Gallery
[edit | edit source]-
Cl2(g) in a gas jar -
gaseous chlorine consists of separate diatomic Cl2 molecules -
crystals of I2(s) -
solid iodine consists of very closely packed I2 molecules
Diatomic halogen molecules
[edit | edit source]| halogen | molecule | structure | model | d(X−X) / pm (gas phase) |
d(X−X) / pm (solid phase) |
|---|---|---|---|---|---|
| fluorine | F2 | 
|
|
143 | 149 |
| chlorine | Cl2 | 
|
|
199 | 198 |
| bromine | Br2 | 
|
|
228 | 227 |
| iodine | I2 | 
|
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|
266 | 272 |
Fluorine
[edit | edit source]Fluorine is the most electronegative element in the periodic table, and is also the most reactive. Flourine is a special case as Fluorine has anomalous properties due to its small size. It has a lower electron affinity than Chlorine due to electron repulsions in the overcrowded outer shell. However, it is a stronger oxidising agent than Chlorine due to its unusually low bond energy. This is due to the repulsions between outer electrons in the F2 molecule.