Question

part vi. write the unabbreviated electron configurations of the following elements:sodiumironbrominebariumneptuniummagnesiumgold

Explanation:

Step1: Recall the Aufbau principle, Pauli exclusion principle, and Hund's rule

These principles govern the filling of electron orbitals. The order of filling is \(1s < 2s<2p < 3s<3p < 4s<3d < 4p<5s<4d < 5p<6s<4f < 5d<6p<7s<5f < 6d\cdots\). Each orbital can hold a maximum of 2 electrons (Pauli exclusion principle), and for degenerate orbitals (same - energy orbitals like \(p\), \(d\), \(f\) orbitals), electrons are filled singly first (Hund's rule).

Step2: Determine the atomic number of each element

• Sodium (\(Na\)): Atomic number \(Z = 11\)
• Fill orbitals: \(1s^{2}2s^{2}2p^{6}3s^{1}\)
• Iron (\(Fe\)): Atomic number \(Z = 26\)
• Fill orbitals: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{6}\)
• Bromine (\(Br\)): Atomic number \(Z = 35\)
• Fill orbitals: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{5}\)
• Barium (\(Ba\)): Atomic number \(Z = 56\)
• Fill orbitals: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}\)
• Neptunium (\(Np\)): Atomic number \(Z = 93\)
• Fill orbitals: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^{14}5d^{10}6p^{6}7s^{2}5f^{4}6d^{1}\)
• Magnesium (\(Mg\)): Atomic number \(Z = 12\)
• Fill orbitals: \(1s^{2}2s^{2}2p^{6}3s^{2}\)
• Gold (\(Au\)): Atomic number \(Z = 79\)
• Fill orbitals: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^{14}5d^{9}\)

Answer:

• Sodium: \(1s^{2}2s^{2}2p^{6}3s^{1}\)
• Iron: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{6}\)
• Bromine: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{5}\)
• Barium: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}\)
• Neptunium: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^{14}5d^{10}6p^{6}7s^{2}5f^{4}6d^{1}\)
• Magnesium: \(1s^{2}2s^{2}2p^{6}3s^{2}\)
• Gold: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^{14}5d^{9}\)