Question

If the number of protons in one atom of an element Y is 20, then the number of electrons in its ion $Y^{2+}$ will be :

(a) 20

(b) 19

(c) 18

(d) 16

Answer 1

Answer :

(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, the number of electrons in its ion $Y^{2+}$ is 18.