WAEC Chemistry 2015 Objective — Question 6
Question 6 of 50 from the West African Examinations Council (WAEC) Chemistry 2015 Objective paper, with the correct answer and a full explanation.
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A metallic ion Z²⁺ with an inert gas structure contains 18 electrons. How many protons are contained in this ion?
- A. 20Correct
- B. 18
- C. 16
- D. 2
Explanation
Z²⁺ has 18 electrons (given). Since forming a 2+ ion means losing 2 electrons, the neutral Z atom has 20 electrons, and since protons=electrons in a neutral atom, proton number=20.
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