The atomic number of an elelment X is 19. The number of electrons in its ion X' will be:
(a) 18 (b) 19 (c) 20 (d) 21

The atomic number of an element Y is 17. The number of electrons in its ion $Y^{-}$ will be
(a) 17 (b) 18 (c) 19 (d) 20

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