The quantum numbers of the last electron of barium are ________. A)n = 6,ℓ = 0,m_ℓ = 1,m_s = 1 B)n = 5,ℓ = 0,m_ℓ = 0,m_s = +1/2 C)n = 6,ℓ = 0,m_ℓ = 1,m_s = +1/2 D)n = 6,ℓ = 1,m_ℓ = 0,m_s = +1/2 E)n = 6,ℓ = 0,m_ℓ = 0,m_s = -1/2

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Quizplus · Accepted Answer

Barium's electron configuration ends in 6s^2, meaning the last electron is in the 6s orbital. For the 6s orbital, n=6, ℓ=0 (s orbital), m_ℓ=0 (only one orientation for s orbital), and m_s can be either +1/2 or -1/2, but since it's the last electron in a filled s orbital, it pairs up with the first with opposite spin, hence m_s = -1/2.

The Quantum Numbers of the Last Electron of Barium Are