Question

An isotope of iron has $28$ neutrons. If the atomic mass is $54$ how many protons does it have?

Answer 1

Hint : The number of neutrons present in the nucleus is calculated by subtracting the mass number of the atom with the atomic number of the atom. The mass number of the atom is the sum of the number of protons and neutrons.

Complete Step By Step Answer:
The number of protons is equal to the atomic number. The number of neutrons is equal to the difference of mass number and atomic number. The number of neutrons present in the nucleus is calculated by subtracting the mass number of the atom with the atomic number of the atom.
The mass number of the atom is the sum of the number of protons and neutrons.
We know that the number of protons is equal to the atomic number. The number of neutrons is equal to the difference of mass number and atomic number. The iron is the chemical element with the symbol $Fe.$ The atomic number $\left( Z \right)$ of $Fe$ is $26$
The iron atom is characterized by an atomic number, $Z=26.$ That is every iron nucleus contains $26-protons$ , $26$ massive positively charged, nuclear particles, by definition.
The nucleus also contains 28 neutrons, $28$ neutral, massive nuclear particles, to give the $^{54}Fe$ isotope. The number of electrons is equal to the number of protons. Number of neutrons is equal to the difference of mass number and atomic number which is the number of protons.

Note :
The mass number is also known as atomic mass and its unit is atomic mass unit. The isotopes of $Fe$ are $^{54}Fe$ , $^{56}Fe$ and , where the mass number is different for each isotope but the atomic number is the same. So, the number of neutrons for each isotope of iron $Fe$ will be different.