Question

How do you find the mass number of an isotope?

Answer 1

Hint There are many elements like hydrogen, carbon, chlorine, etc having different types in which the atomic numbers are the same but the number of protons is different and are called an isotope. The number of neutrons is used to find the mass number of the isotope.

Complete step by step answer:
There are many elements like hydrogen, carbon, chlorine, etc having different types in which the atomic numbers are the same but the number of protons is different and are called an isotope. The isotope having atomic number 1 is hydrogen, deuterium, and tritium. The number of neutrons in hydrogen is zero, the number of neutrons in deuterium is one and the number of neutrons in the tritium is two. Since all of them have the atomic number 1 which means that the number of protons and the number of the electron is one. To find the mass number of the element can be calculated by adding the number of proton and neutron, therefore the mass number of hydrogen is 1 ( 1 + 0), the mass number of deuterium is 2 (1 + 1), and the mass number of tritium is 3 (1 + 2). So, the mass of the isotope is calculated with the atomic number and number of neutrons in the atom. We can represent the hydrogen, deuterium, and tritium by $_{1}^{1}H$, $_{1}^{2}D$, and $_{1}^{3}T$.

Note: The carbon atom has 6 neutrons and has a mass of 12, the carbon having 7 neutrons have a mass of 13. The nitrogen atom has 7 neutrons and has a mass of 14, the nitrogen atom having 8 neutrons will have a mass of 15.