## University Physics with Modern Physics (14th Edition)

For n = 1, $l$ can only be 0, and $m_l$ can only be 0. Here are the possible $(n, l, m_l,m_s)$ pairs for n =1: $$(1,0,0,+\frac{1}{2}) (1,0,0,-\frac{1}{2})$$ For n = 2, $l$ can take on the values 1 and 0. For $l=1$, $m_l$ can be $\pm l$. Here are the possible $(n, l, m_l,m_s)$ pairs for n =1: $$(2,1,0,+\frac{1}{2}) (2,1,0,-\frac{1}{2})$$ $$(2,1,1,+\frac{1}{2}) (2,1,1,-\frac{1}{2})$$ $$(2,1,-1,+\frac{1}{2}) (2,1,-1,-\frac{1}{2})$$ $$(2,0,0,+\frac{1}{2}) (2,0,0,-\frac{1}{2})$$ Those cover the 10 electrons in neon.