Compare and contrast the Lewis structures of krypton and radon.
The correct answer and explanation is :
Correct Answer:
Krypton (Kr) and Radon (Rn) are both noble gases, and their Lewis structures are similar, consisting of eight valence electrons represented as four pairs of dots around the element symbol. However, there are subtle differences based on their positions in the periodic table and atomic properties.
300-Word Explanation:
Krypton (Kr) and Radon (Rn) belong to Group 18 (the noble gases) of the periodic table. Noble gases are characterized by having full outer electron shells, which make them chemically inert under normal conditions. The Lewis structures of both Kr and Rn reflect their stable octet configuration.
For krypton, with an atomic number of 36, the electron configuration is:
- 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶
This shows that krypton has eight valence electrons in the 4th shell (4s² 4p⁶). In its Lewis structure, krypton is represented by the symbol “Kr” surrounded by four pairs of dots, each pair representing one electron pair:
..
: Kr :
..Radon, with an atomic number of 86, has a similar configuration but in the 6th shell:
- 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶
Radon also has eight valence electrons (6s² 6p⁶), so its Lewis structure is:
..
: Rn :
..Comparison and Contrast:
- Similarity: Both Kr and Rn have eight valence electrons and full outer shells, so their Lewis structures are the same in appearance.
- Difference: Rn is heavier and more polarizable than Kr. Though its Lewis structure looks the same, Rn can form compounds more easily (e.g., with fluorine) due to relativistic effects and weaker hold on outer electrons, which krypton does not usually do.
- Conclusion: While their Lewis structures look identical—both showing four pairs of valence electrons—the chemical reactivity and physical properties differ due to their position in the periodic table and atomic size.