The physical and chemical properties of elements are periodic functions of their electronic configuration is called as Bohr's periodic law.It is also known as long form periodic table. In long form periodic table, there are 7 periods and 18 groups.
Seven periods :
-The first period contain 2 elements.
-Second period and third period contains eight elements.
-Fourth and fifth periods contain eighteen elements.
-Sixth period contains thirty elements .
-Seventh period is incomplete period and it contains nineteen elements.
There are 18 groups in the long form periodic table. The 18 groups are divided into three blocks s, p and d.
-’s’ block contains two groups.
-’p’ block contains six groups
-‘d’ block contains ten groups.
-‘s’ block and ‘p’ block are called as Representative elements’’ .
-'d 'block elements are called as "Transition elements".
- 'f’ block elements are called as inner transition elements.