Question

The following table gives the number of protons and neutrons in the nuclei of various atoms. Which atom is the isotope of atom A? Which atom has the same mass number as atom A?

Protons. Neutrons
Atom A. 32. 39
Atom B. 32. 38
Atom C. 38. 50
Atom D. 33. 38

Answer 1

Atom B, which has 32 protons and 38 neutrons, is the isotope of atom A. None of the listed atoms have the same mass number as atom A.

Step-by-step explanation:

The isotope of atom A would be the atom with the same atomic number (number of protons) but a different number of neutrons. This is atom B, which has 32 protons like atom A, but 38 neutrons instead of 39. The atom that has the same mass number as atom A would have the same total number of protons and neutrons.

Atom A has a mass number of 71 (32 protons + 39 neutrons), but none of the other atoms listed have this mass number. Isotopes are forms of the same element (having the same number of protons) but with differing numbers of neutrons, resulting in different mass numbers.

Atom B, with the same atomic number but a different neutron number, is thus an isotope of Atom A. The mass number, also known as atomic mass, is calculated as the sum of an element's protons and neutrons.