An ion with mass

Given:

Mass Number = 37

Percentage of neutron = 11.1% more as compared electrons

Let Number of electrons = number of protons = p

Let number of protons = p

Let number of neutrons= n

p + n = 81

p + {p + [11.1× p] / 100} = 37

p + 1.111p = 37

2.111p = 37

p = 37 / 2.111

p = 17.527

p = 17

Atomic Number = 17

The element is chlorine.

The atomic symbol is 37₁₇Cl.