Which of the following pairs of elements are expected to have the most similar chemical properties?

• A. Na and K
• B. O and Cl
• C. C and N
• D. Mg and Al

Answer: (A)

Verified step by step guidance

1. Understand that elements with similar chemical properties typically belong to the same group (column) in the periodic table because they have the same number of valence electrons.
2. Identify the groups of each element in the pairs: Na (Sodium) and K (Potassium) are in Group 1 (alkali metals), O (Oxygen) and Cl (Chlorine) are in Groups 16 and 17 respectively, C (Carbon) and N (Nitrogen) are in Groups 14 and 15 respectively, Mg (Magnesium) and Al (Aluminum) are in Groups 2 and 13 respectively.
3. Recognize that elements in the same group have similar valence electron configurations, which leads to similar chemical behavior.
4. Since Na and K are both alkali metals in Group 1, they have the most similar chemical properties among the given pairs.
5. Conclude that the pair Na and K is expected to have the most similar chemical properties because they share the same group and similar valence electron configuration.