What atom matches this electron configuration

What atom matches this electron configuration? [Xe] 6s² 4f¹⁴ 5d⁹² A) Pt B) Hg C) Au D) Th

The Correct Answer and Explanation is:

The given electron configuration is: [Xe]6s24f145d10[Xe] 6s^2 4f^{14} 5d^{10}[Xe]6s24f145d10.

To identify the element, we need to analyze the configuration step by step:

1. The [Xe] core configuration represents the electron configuration of xenon (atomic number 54). This leaves us with the outer electrons after xenon’s core.
2. 6s² indicates two electrons in the 6s orbital.
3. 4f¹⁴ means there are 14 electrons in the 4f orbital, which corresponds to a completely filled 4f subshell.
4. 5d¹⁰ means there are 10 electrons in the 5d orbital, which corresponds to a completely filled 5d subshell.

Now, let’s count the total number of electrons:

• The xenon core provides 54 electrons.
• 2 electrons in the 6s orbital.
• 14 electrons in the 4f orbital.
• 10 electrons in the 5d orbital.

This gives a total of 54+2+14+10=8054 + 2 + 14 + 10 = 8054+2+14+10=80 electrons, which means the atom must have an atomic number of 80.

Looking at the periodic table, element number 80 is Mercury (Hg).

Therefore, the correct answer is B) Hg (Mercury).

Mercury is a transition metal in Group 12 of the periodic table, and its electron configuration matches the one given in the problem. The elements provided as options (Pt, Au, Th) have different atomic numbers and electron configurations:

• A) Pt (Platinum) has an atomic number of 78, with the electron configuration ending in 5d95d^95d9.
• C) Au (Gold) has an atomic number of 79, with the electron configuration ending in 5d106s15d^{10} 6s^15d106s1.
• D) Th (Thorium) has an atomic number of 90, and its electron configuration ends in 6d27s26d^2 7s^26d27s2.

Thus, the electron configuration provided is specific to Hg (Mercury).