When n = 2, l can be 0 or 1.
The Principal Quantum Number (n) describes the size and energy of the electron shell. n = 2 corresponds with the second period (row) of the periodic table, beginning with lithium (1s22s1) and ending with neon (1s22s22p6). In electron configurations, n values are given as the coefficients (ex. the 1 in 1s2).
The Angular Momentum Quantum Number (l) specifies the shape(s) of the subshell(s) of orbitals. It's value is always related to n because l can take on integer values between 0 and n - 1. When n = 2, l can be 0 or 1. l = 0 corresponds with s (spherical) subshells and l = 1 corresponds with p (dumbbell or lobed) subshells. In electron configurations, l values are given as the letters (ex. the s in 1s2).