Question

noble gas configuration practice
complete the following practice assignment.
1
multiple choice 1 point
what is the predicted noble gas configuration of gold (au)?
xe4f^{14}5d^{10}6s^{1}
rn6s^{2}4f^{14}5d^{9}
xe6s^{2}4f^{14}5d^{9}
kr6s^{2}5d^{9}

Explanation:

Step1: Determine the noble gas core

Gold (Au) has an atomic number of 79. The noble gas before Au is Xenon (Xe) with an atomic number of 54.

Step2: Fill the remaining orbitals

After [Xe], we fill the 4f, 5d, and 6s orbitals. The 4f orbital can hold 14 electrons, the 5d orbital can hold 10 electrons, and the 6s orbital can hold 2 electrons. But due to the stability of a full - filled 5d orbital and a half - filled 6s orbital, one electron from the 6s orbital moves to the 5d orbital. So the electron configuration is [Xe]4f¹⁴5d¹⁰6s¹.

Answer:

[A. [Xe]4f¹⁴5d¹⁰6s¹]