Modern inorganic chemistry

312 GROUP VI!: THE HALOGENS

0

g

.

o

400

*:

CL

cL

E

200

, 1500

co

IOOO,

(^1) Atomic radius
ionic radius
Ist ionisation energy
enthalpy of otornisation
o
120 g
_oE
ROow
10 20 30 40 50
Atomic number
60
Figure 11.1. Properties of Group VII elements
Numerous ionic compounds with halogens are known but a
noble gas configuration can also be achieved by the formation of a
covalent bond, for example in halogen molecules, X 2 , and hydrogen
halides, HX. When the fluorine atom acquires one additional electron
the second quantum level is completed, and further gain of electrons
is not energetically possible under normal circumstances, i.e.