The elements of Group 17, the Halogens, are:
symbol
electron
configuration
fluorine
F
[He]2s22p5
chlorine
Cl
[Ne]3s23p5
bromine
Br
[Ar]3d104s2 4p5
iodine
I
[Kr]4d105s2 5p5
astatine
At
[Xe]4f14 5d106s2 6p5
ELEMENT
Fluorine
Chlorine
Bromine
Iodine
STATE AT ROOM
TEMP.
Pale Yellow Gas
Greenish Gas
Reddish brown liquid
Violet black Solid
Bond Enthalpy
Bond enthalpy is the heat needed to break one mole
of a covalent bond to produce individual atoms,
starting from the original substance in the gas state,
and ending with gaseous atoms.
e.g.
Bond Enthalpy
Electron affinity (E.A.)
The first electron affinity is the energy released
when 1 mole of gaseous atoms acquire
an electron to form 1 mole of gaseous 1- ions.
In symbol terms:
Q. 12
Why is fluorine a much stronger oxidizing agent
than chlorine?
Oxidizing strength : F2 >Cl2 >Br2 >I2
Halogen Displacement reactions
Cl2 + 2Br-→ 2Cl- + Br2
Cl2 + 2I-→ 2Cl- + I2
Br2 + 2I-→ 2Br- + I2
1) Halogen + metal:
Halides
+
+
Na
Cl
Halogen + metal
Cl
Na
ionic salt
2) Halogen + non-metal:
H
+
Cl
Halogen + non-metal
Cl
H
covalent molecule
Interhalogen compounds
e.g.
ClF3
IF5
IF7
Q 13
Indicate the hybridization and draw the structures
of following species:
IF7, ICl4-
Q. 14
Write a balanced equation for the reaction of
F2 with water