Question

1.Calculate the number of electrons and neutrons present in ²⁷Al_13.

Answer 1

Al has mass number of 27 and atomic number of 13
So atomic number = number of protons = 13 and since there is no charge on the given atom so the number of electrons is also 13
and Mass number = number of neutrons + number of protons = 13 + n = 27
therefore n= 27 - 13 = 14 = number of neutrons.