In which set of elements would all members be expected to have very similar chemical properties?

• A. C, P, S
• B. Na, K, Rb
• C. Mg, Al, Si
• D. N, O, F

Answer: (B)

Verified step by step guidance

1. Recall that elements in the same group (vertical column) of the periodic table have similar chemical properties because they have the same number of valence electrons.
2. Identify the groups for each set of elements: C (carbon), P (phosphorus), and S (sulfur) are in different groups (14, 15, and 16 respectively); Mg (magnesium), Al (aluminum), and Si (silicon) are in groups 2, 13, and 14 respectively; N (nitrogen), O (oxygen), and F (fluorine) are in groups 15, 16, and 17 respectively.
3. Check the set Na (sodium), K (potassium), and Rb (rubidium): all three are in group 1 (alkali metals), meaning they have one valence electron and similar chemical behavior.
4. Conclude that the set with all members in the same group, and thus expected to have very similar chemical properties, is Na, K, and Rb.
5. Remember that elements in the same period (horizontal row) do not necessarily have similar chemical properties, so similarity is best predicted by group membership.