Which element has the following ground state electron configuration: 1s^2 2s^2 2p^6 3s^2 3p^5?

• A. Sodium (Na)
• B. Fluorine (F)
• C. Chlorine (Cl)
• D. Argon (Ar)

Answer: (C)

Verified step by step guidance

1. Identify the electron configuration given: \$1s^2 2s^2 2p^6 3s^2 3p^5$.
2. Count the total number of electrons by adding the superscripts: \$2 + 2 + 6 + 2 + 5$.
3. Sum these to find the total number of electrons, which corresponds to the atomic number of the element.
4. Use the periodic table to match the atomic number to the element symbol and name.
5. Confirm that the element with this atomic number has the given electron configuration, which corresponds to Chlorine (Cl).