SSC MTS EXAM

Detailed explanation-1: -The second period contains the elements lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, and neon. In a quantum mechanical description of atomic structure, this period corresponds to the filling of the second (n = 2) shell, more specifically its 2s and 2p subshells.

Detailed explanation-2: -Period 1 has 2 elements while period 2 and period 3 have 8 elements each.

Detailed explanation-3: -Second and third period of the modern periodic table contains 8 elements.