O Levels Chemistry (5070)•5070/12/M/J/21
Explanation
Evaluating atomic structure statements Steps:
- Examine W and X: same atomic number (protons) but different mass numbers (neutrons), confirming isotopes of one element.
- Check Y: 5 valence electrons place it in group V (15) of the Periodic Table.
- Analyze Z: equal protons and electrons indicate a neutral atom, not a cation.
- Match correct statements (1 and 2) to option A.
Why A is correct:
- Isotopes share atomic number per definition; group V requires 5 outer electrons by Periodic Table structure.
Why the others are wrong:
- B includes false statement 3 (Z neutral, not cation).
- C omits true statement 2 (Y in group V).
- D excludes true statement 1 (W, X isotopes) and includes false 3.
Final answer: A
Topic: Atomic structure and the Periodic Table
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