How does the electronic configuration of an atom of an element relate to its position in the modem periodic table? Explain with one example.
The electronic configuration of an atom of an element gives its position in the modern periodic table. (i) The ‘period number’ of an element is equal to the number of electron shells in its atom. (ii) The group number of an element having upto two valence electrons is equal to the number of valence electrons. The group number of an element having more than 2 valence electrons is equal to the number of valence electrons plus 10. Example: If the electronic configuration of an element is 2, 8, 7. Then its period number is 3 as it has three electrons shells. Its group number is 17 as it has 7 valence electrons. (∵ Group no. = 7 + 10 = 17)
