Question

Which of the ions are isoelectronic ?

• A. Be²⁺, Mg²⁺, Al³⁺
• B. Al³⁺, Ca²⁺, Sr²⁺
• C. Ca²⁺, K⁺, S^2–
• D. K⁺, Na⁺, Li⁺

Answer 1

Answer: (C)

Ca²⁺, K⁺, S^2–

Answer 2

K⁺, S^2–, Ca²⁺ all are isoelectronic with 18 electrons