Question

what is meant by electronic configuration?
explain with an example ?

Answer 1

The arrangements of electrons in the orbit of an atom is called electronic configuration.
eg; magnesium has 12 electrons .its configuration is 1s^{2} 2 s^{2} 2 p^{2} 3 s^{2} 

Answer 2

Electronic Configuration is the mode of arrangement of electrons in their orbits or shells.
Example: Sodium =[2,8,1]
Which means first shell of sodium contains 2 electrons.
Second shell of sodium contains 8 electrons
third shell of sodium contains 1 electron.