Question

An isotope of an element having a number of neutrons 9 and its mass number is 17. Write the name and an atomic number of the element.

Answer 1

Answer:

The element is oxygen and the atomic number is 8.

Explanation:

Mass number of an atom is given by the sum of the protons and neutrons in an atom. The atomic mass of an atom is the same as the number of protons in an atom.

Isotopes of an element differ in the mass number but have the same atomic mass. The difference is brought in by the number of neutrons.

In this case we have an isotope having 9 neutrons and a mass number of 17.

   Mass number = Protons + neutrons

   Protons = Mass number  - neutrons

   Protons  = 17 - 9  

                 = 8

This isotope has 8 protons, meaning its atomic mass is also 8 a.m.u

The element in the periodic table that has an atomic mass of 8 is oxygen.