Question

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

Answer 1

(b) 18
Anion Y^- has one more electron than its neutral atom. Y atom has 17 electrons and therefore, in Y^- ,number of electrons will be 18 (17 + 1).