Question

An anion X³⁻ has 36 electrons and 45 neutrons.What are atomic number & mass number? *

2 points

(a) 33 & 78

(b) 36 & 81

(c) 34 & 78

(d) 35 & 78

​

Answer 1

Answer:

a) 33 & 78

Explanation:

$X^{-3}$ means 3 electrons are taken

Original element got (36 - 3) = 33 electrons

Atomic Number = No. of Electrons = 33

Mass number = Electrons + Nuetrons = (33 + 45) = 78