Question

THE NUMBER OF ELECTRONS SHELLS IN ELEMENTS OF PERIOD 1,2,3​

Answer 1

The simplest atoms, hydrogen and helium, are found in row 1, or the first period. These atoms have electrons occupying the energy level n=1. Moving down, row 2, or period 2, contains the elements Li (lithium) through Ne (neon).

Answer 2

The simplest atoms, hydrogen and helium, are found in row 1, or the first period. These atoms have electrons occupying the energy level n=1. Moving down, row 2, or period 2, contains the elements Li (lithium) through Ne (neon)

Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2(n2) electrons.