Question

Explain why 8 elements in 3rd period

Answer 1

The number of electrons present in the outermost shell of an atom is given by the formula 2n2, where n stands for the number of the given shell from the nucleus of an atom. All the elements present in the 3rdperiod have 3 shells. Therefore , n = 3 ,

2n2 = 2 x (3)2 = 2 x 3 x 3 = 2 x 9 = 18

Since the outermost or valence shell can accommodate only 8 electrons . Therefore , the 3rd period contains only 8 electrons .