ions, molecular ions and free radicals.

1. Zahra Fazal

2. Ion is an atom or group of atom having
charge on it.
The charge may be positive or negative.

3. Ions
Cation
Positive
charge
Anion
Negative
charge

4.  An atom and group of atom having
positive charge is called cation.

5.  Cation is formed when an atom loses electron
from its outermost shells.
 For example:
 K+ , Na+, Ca2+

7.  An atom and group of atom having
negative charge is called anion.

8.  Anion is formed by the gain of electrons
or by addition of electron to an atom.
 For example:
 O2-, CL-

10. When molecules loses or gain
electron , it forms a molecular ion.

11.  Molecular ions are of two types:
 Cationic molecular ion
 Anionic molecular ion

12.  When a molecule loses an electron it form
cationic molecular ion
 It carries positive charge

13. Cationic molecular ions are more
abundant than anionic molecular
ions
For example CH4
+, N2+, He+

14.  When a molecule gains electron it form
anionic molecular ion.
 It carries negative charge.

15.  When gases are bombarded with high
energy electrons in a discharge tube, they
ionize to give molecular ions.

16. Free radicals are atoms or group of
atoms possessing odd number of
(unpaired) electrons

17. It is represented by putting a dot over
the symbol of an element e.g. H. ,
Cl. ,H3C.

18.  Free radicals are generated by the
homolytic (equal) breakage of the bond
between two atoms when they absorb heat
or light energy.