According to Bohr’s model of an atom, orbits or shells of an atom are represented by K,L, M,N….. or the numbers 1,2,3, 4… respectively. The maximum number of electron in K shell is equal to 2n² where n is the orbit number. Hence, first orbit or K-shell will be = 2 × 12 = 2 electrons . Second orbit or L-shell will be = 2 × 22 = 8 electrons.