To which group of the periodic table does an element with the electron configuration 1s2 2s2 2p1 belong?

• A. Group 14 (Carbon group)
• B. Group 2 (Alkaline earth metals)
• C. Group 1 (Alkali metals)
• D. Group 13 (Boron group)

Answer: (D)

Verified step by step guidance

1. Identify the element's highest energy level and the type of orbital where the last electron is added. The given electron configuration is \$1s^2\ 2s^2\ 2p^1\(, so the highest energy level is \)n=2\( and the last electron enters a \)p$ orbital.
2. Determine the total number of valence electrons by counting electrons in the outermost shell (here, the \$2s^2\( and \)2p^1$ electrons). This gives a total of 3 valence electrons.
3. Recall that the group number for main-group elements can be related to the number of valence electrons. Elements with 3 valence electrons belong to Group 13 (Boron group).
4. Match the valence electron count to the periodic table group: since the element has 3 valence electrons, it belongs to Group 13, which includes boron and its congeners.
5. Confirm that the element is not in Group 1 (1 valence electron), Group 2 (2 valence electrons), or Group 14 (4 valence electrons), thus verifying that Group 13 is the correct group.