Which element typically has 6 valence electrons in its outermost shell (main-group elements)?

• A. Carbon (C)
• B. Nitrogen (N)
• C. Oxygen (O)
• D. Neon (Ne)

Answer: (C)

Verified step by step guidance

1. Recall that the number of valence electrons for main-group elements corresponds to their group number in the periodic table. For groups 1 and 2, the valence electrons equal the group number, and for groups 13 to 18, the valence electrons equal the group number minus 10.
2. Identify the group number for each element: Carbon (C) is in group 14, Nitrogen (N) is in group 15, Oxygen (O) is in group 16, and Neon (Ne) is in group 18.
3. Calculate the valence electrons for each element using the rule: valence electrons = group number - 10 for groups 13 to 18. For example, Oxygen in group 16 has 16 - 10 = 6 valence electrons.
4. Confirm that Oxygen (O) has 6 valence electrons, which matches the question's requirement for the element with 6 valence electrons in its outermost shell.
5. Understand that Neon (Ne), being a noble gas in group 18, has a full outer shell with 8 valence electrons, and Carbon and Nitrogen have fewer valence electrons (4 and 5 respectively), so they do not fit the criteria.