Question

How many neutrons are in an atom of sulfur with a mass number of 35?

Answer 1

Hint: The atom is composed of protons, neutrons and the electrons. The electrons have the negative charge on them while the protons have the positive charge on them and the neutrons are neutral in nature with no charge. The mass number of the atom is also known as the atomic mass number which is the sum of the number of protons and number of neutrons present in the atom.

Complete step by step answer:
the mass number is equal to the total number of nucleons. The mass number is approximately equal to the atomic mass of the atom which has been expressed in Dalton. The protons and neutrons are referred to as baryons. So the total mass number A is equal to the sum of the number of protons and number of neutrons. The number of the proton is equal to the atomic number. The symbol to represent the atomic number or the number of protons is Z. so the relationship between the mass number and the protons and neutrons is the following:
$$N = A - Z$$
Here N is the number of neutrons, A is the mass number and Z is the atomic number.
A is equal to 35 and the Z or atomic number of sculpture is 16. On substituting the value we get,
$$N = 35 - 16$$
N= 19

So the number of neutrons in an atom of sulphur of mass number 35 is 19.

Note: The number of protons, atomic number and the number of electrons are equal. The mass number and the atomic number are always present as the whole number as they are obtained by counting the total number of protons, neutrons and the electrons. We know that the protons and neutrons are combined in nucleus so they are known as nucleons.