Question

fix any errors in these proposed electron configurations.
number of
electrons in
atom proposed electron configuration
13 1s^{4}2s^{4}2p^{5}
9 1s^{2}2s^{2}3s^{2}2p^{3}
11 1s^{2}1p^{6}2s^{2}2p^{1}

Explanation:

First row (13 electrons):

• Error: The maximum number of electrons in an \(s\) - orbital is \(2\), and in a \(p\) - orbital is \(6\). Here, \(1s^{4}\) and \(2s^{4}\) are incorrect.
• Correction:
• Fill orbitals in the order \(1s<2s < 2p<3s\).
• \(1s^{2}2s^{2}2p^{6}3s^{1}\) (using the Aufbau principle: electrons fill orbitals from the lowest - energy to the highest - energy orbitals. The energy order of orbitals relevant here is \(E(1s)<E(2s)<E(2p)<E(3s)\))

Second row (9 electrons):

• Error: Orbitals should be filled in the order \(1s<2s < 2p\) before filling \(3s\). The \(3s\) orbital is filled before \(2p\) is completely filled in the proposed configuration.
• Correction:
• Fill orbitals in the order \(1s<2s < 2p\).
• \(1s^{2}2s^{2}2p^{5}\) (since \(n = 1\) shell (\(1s\)) can hold \(2\) electrons, \(n=2\) shell: \(2s\) (holds \(2\) electrons) and \(2p\) (holds \(5\) electrons out of a maximum of \(6\)) )

Third row (11 electrons):

• Error: There is no \(1p\) orbital. The first shell (\(n = 1\)) has only an \(s\) - orbital (\(1s\)).
• Correction:
• Fill orbitals in the order \(1s<2s < 2p<3s\).
• \(1s^{2}2s^{2}2p^{6}3s^{1}\) (using the Aufbau principle: \(1s\) (2 electrons), \(2s\) (2 electrons), \(2p\) (6 electrons), and then \(3s\) (1 electron))

Answer:

number of electrons in atom	corrected electron configuration
9	\(1s^{2}2s^{2}2p^{5}\)
11	\(1s^{2}2s^{2}2p^{6}3s^{1}\)