Answer
The lithium atom has $3$ electrons. At ground state of the lithium atom, $2$ of $3$ electrons fit into the lowest-energy subshell, the $1s$ subshell with quantum numbers $(n,l,m_l,m_s)$ of $(1,0,0,-\frac{1}{2})$ and $(1,0,0,+\frac{1}{2})$ respectively. The remaining $1$ electron fill the next lowest energy subshell, the $2s$ subshell with quantum numbers $(n,l,m_l,m_s)$ of $(2,0,0,\mp\frac{1}{2})$
Work Step by Step
The lithium atom has $3$ electrons. At ground state of the lithium atom, $2$ of $3$ electrons fit into the lowest-energy subshell, the $1s$ subshell with quantum numbers $(n,l,m_l,m_s)$ of $(1,0,0,-\frac{1}{2})$ and $(1,0,0,+\frac{1}{2})$ respectively. The remaining $1$ electron fill the next lowest energy subshell, the $2s$ subshell with quantum numbers $(n,l,m_l,m_s)$ of $(2,0,0,\mp\frac{1}{2})$
