A possible set of quantum numbers to describe an electron in a 4s subshell is A) n = 4, l = 0, m_l = 1 , m_s = +1/2 B) n = 4, l = 0, m_l = 0, m_s = - 1/2 C) n = 4, l = 1, m_l = 1, m_s = +1/2 D) n = 3, l = 1, m_l = 1, m_s = - 1/2 E) n = 3, l = 0, m_l = 0, m_s = +1/2

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The electron in a 4s subshell has a principal quantum number (n) of 4 and an angular momentum quantum number (l) of 0 (since it is an s subshell). The magnetic quantum number (ml) for l = 0 is always 0. Finally, the electron will have a spin (ms) of -1/2 in the 4s subshell according to the Aufbau principle which dictates that electrons fill the lowest energy subshell available first. Thus, the set of quantum numbers that describes an electron in a 4s subshell is: n=4, l=0, ml=0, ms=-1/2 which corresponds to Choice B.

A Possible Set of Quantum Numbers to Describe an Electron