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JAMB Chemistry 1993 Question 9

Question 9

Atomic Structure

An element, E, has the electronic configuration 1s22s22p63s23p3. The reaction of E with a halogen X can give

  1. A.EX3 and EX5
  2. B.EX3 only
  3. C.EX5 only
  4. D.EX2 and EX3
Show the answer and explanation

Answer: A (EX3 and EX5)

Explanation

E is phosphorus (5 valence electrons). It can use 3 of them or, using its empty 3d orbitals, all 5, giving EX3 and EX5 (e.g. PCl3 and PCl5).