Class X Modern Periodic Table

Atomic number is the basis for modern periodic table. Atomic number is the number of protons in the nucleus, it is also equal to the number of electrons in the atom.
Electronic configuration is the arrangement of electrons in an atom around its nucleus.

The important features of Bohr's atomic theory are:
Electrons occur in definite electronic shells.
The shells in an atom can be named alphabetically as K,L,M,N and so on. Read More at https://www.learnnext.com/lesson/CBSE-X-Science-Modern-Periodic-Table.htm