The ion of an element has 3 positive charges. The mass number of atom of this element is 27 and the number of neutrons is 14. What is the number of electrons in the ion?

Mass number of atom = 27
Number of neutrons = 14
Number of protons = Mass number$-$Number of neutrons
Number of protons = 27$-$14
Number of protons = 13

As the number of protons = Number of electrons
So, Number of electrons = 13
But the element has 3 positive(+3) charge that means this element has the deficiency of 3 electrons.
So, Number of electrons = 13$-$3 =10

Hence, the number of electrons in the given ion is 10.