Which element has the electron configuration [Kr] 5s² 4d¹⁰ 5p³?
Answer and explanation
Correct answer: B. Antimony (Sb)
- Step 1: Identify the period and group: Period 5 (valence shell n=5) and Group 15 (p³ configuration).
- Step 2: Calculate total atomic number: Kr has 36 electrons + 2 (5s) + 10 (4d) + 3 (5p) = 51 electrons. Element 51 is Antimony (Sb).
Answer
Antimony (Sb).
Why not the others: Arsenic is in Period 4 (Z=33); Bismuth is in Period 6 (Z=83); Tellurium has 5p⁴ (Z=52).
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