1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 is the electron configuration for which element?

• A. Magnesium (Mg)
• B. Potassium (K)
• C. Sodium (Na)
• D. Calcium (Ca)

Answer: (B)

Verified step by step guidance

1. Identify the electron configuration given: \$1s^2 2s^2 2p^6 3s^2 3p^6 4s^1$.
2. Count the total number of electrons by adding the superscripts: \$2 + 2 + 6 + 2 + 6 + 1$.
3. Recall that the number of electrons in a neutral atom equals its atomic number.
4. Match the total number of electrons to the element with the corresponding atomic number on the periodic table.
5. Confirm that the element with this atomic number is Potassium (K), which has atomic number 19.