Given this set of quantum numbers for a multielectron atom 2, 0, 0, and -1/2. The next higher allowed set of n and l for this atom in its ground state

For the quantum numbers 

2   ,0    ,0    ,1/2  it is 2s- orbital. 

possible lelctronic configuration : : 2s¹ 2s².

next possible orbital is : 2p orbital 

which has n=2 and l=1.