Question:
The ion of an element has 3 positive charges. Mass, number of the atom is 27 and the number of neutrons is 14 . What is the number of electrons in the ion?
(a) 13
(b) 10
(c) 14
(d) $16 .$
Solution:
(b) The ion has 13 protons $(27-14)$ and 10 electrons. It is $\mathrm{Al}^{3+}$ ion.