Question

Which of the following is not correct?

• A. \(2p^ 6\)
• B. \(3s^1\)
• C. \(4f^{ 12}\)
• D. \(2d^ 3\)

Answer 1

The Correct Option is D

In the context of electron configurations and quantum chemistry, each atomic orbital can hold a specific number of electrons, and certain rules determine how electrons populate these orbitals. Let's explore the legitimacy of the given options based on their possible electron configurations:

\(2p^6\): The 'p' orbital can hold a maximum of 6 electrons. Therefore, this configuration is correct.

\(3s^1\): The 's' orbital can hold a maximum of 2 electrons, and having 1 electron is acceptable. Thus, this configuration is also correct.

\(4f^{12}\): The 'f' orbital can hold a maximum of 14 electrons. With 12 electrons, this is a valid configuration.

\(2d^3\): The 'd' orbital cannot exist in the second energy level (n=2) as the 'd' orbitals start from the third energy level (n=3). Therefore, this configuration is not possible, making it incorrect.

The correct answer is \(\mathbf{2d^3}\) as it represents an impossible electron configuration according to quantum mechanical principles.

Answer 2

Electron configurations must follow the correct order of orbital filling based on the Aufbau principle and the available sublevels in each shell:

• \(2p^6\): Correct — the p-subshell exists in the 2nd shell and can hold up to 6 electrons.
• \(3s^1\): Correct — the s-subshell exists in the 3rd shell and can hold up to 2 electrons.
• \(4f^{12}\): Correct — the f-subshell starts appearing from the 4th shell and can hold up to 14 electrons.
• \(2d^3\): Incorrect — the d-subshell does not exist in the 2nd shell.

Correct Answer: \(2d^3\)