Question

An atom with an atomic mass of 89 and an atomic number of 39 has how many neutrons

Answer 1

The correct answer is 50

Explanation:

The atom is known as the smallest unit of matter, this is composed of a nucleus with neutrons and protons (particles positively charged), as well as electrons (particle negatively charged) that are outward the nucleus. In this context the atomic number of an atom is the same that the number of protons which is unique to each element, this means the atom of the question contains 39 protons as the atomic number is equivalent to 39; in the same way, the atomic mass refers to the sum of protons plus neutrons that in this case is 89.

According to this, the number of neutrons can be found by subtracting the number of protons expressed in the atomic number from the atomic mass that includes both the protons and the neutron which is shown below.

89 (number of protons and neutrons) - 39 (number of protons) = 50 neutrons

Answer 2

89 - 39 = 50

The atom has 50 neutrons. Hope this helps! :)