An element ‘X’ has atomic mass number = 27. If the number of electrons = 13. The number of neutrons will be _____.
14
Atomic mass number = number of protons + number of neutrons
Since an atom is neutral, number of protons = number of electrons, which is necessary for charge balance.
Thus the number of protons = 13, since number of electrons = 13.
So number of neutrons will be 27 – 13 = 14