definition of free radical
Free radical is a free atom with an unpaired electron. This free unpaired electron is also called odd electron.
The examples of free radical
When a chlorine molecule is break into two chlorine atom, each chlorine atom contains one unpaired electron. Each chlorine with unpaired or odd electron is called free radical.
One of the most important properties of free radical is that free radicals are highly reactive. The cause of the high reactivity of free radicals are their tendency of filling the octate is very high. Hence, free radicals shows higest tendency of gaining electron.