Which element has the electron configuration 1s2 2s2 2p6 3s2 3p6 4s2 3d8?

• A. Nickel (Ni)
• B. Copper (Cu)
• C. Zinc (Zn)
• D. Iron (Fe)

Answer: (A)

Verified step by step guidance

1. Identify the total number of electrons in the given electron configuration: \$1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^8\(. Add the electrons in each subshell: \)2 + 2 + 6 + 2 + 6 + 2 + 8$.
2. Sum these electrons to find the atomic number corresponding to this configuration, since the number of electrons in a neutral atom equals its atomic number.
3. Recall that the atomic number corresponds to a specific element on the periodic table.
4. Match the atomic number found to the element options given: Nickel (Ni), Copper (Cu), Zinc (Zn), Iron (Fe).
5. Confirm that the electron configuration ends with \$3d^8\(, which is characteristic of Nickel (Ni), as Copper and Zinc have different \)3d\( subshell fillings, and Iron has fewer \)3d$ electrons.