Question

If the number of protons in one atom of an element Y is 20, then the number of electrons in its ion Y²⁺will be:
(a) 20
(b) 19
(c) 18
(d) 16

Answer 1

(c) 18
Number of protons is equal to the number of electrons in an atom. It is given that an atom of an element Y contains 20 electrons. Therefore, number of electrons in its ion Y²⁺ is 18 (20 → 2).