Question

X and y are elements that are isotopes to each other. Which of the following is true about x and y?

1) They have the same atomic number
2) They have the same mass number
3) They have the same number of neutrons
4) They have the same number of protons

Answer 1

Isotopes of an element, such as x and y, have the same number of protons, which means they have the same atomic number. They differ, however, in their neutron counts, which results in different mass numbers. The correct option is 1.

Step-by-step explanation:

If x and y are elements that are isotopes to each other, several key characteristics must be considered to understand their relationship. Firstly, isotopes are atoms of the same element, which means they have identical atomic numbers because they have the same number of protons. This directly addresses one of the provided statements and shows that the correct answer is that they have the same number of protons.

Isotopes, by definition, have different neutron counts, which leads to different mass numbers. This fact alone eliminates the other options provided since isotopes do not have the same mass number or the same number of neutrons. However, they do have the same atomic number because the atomic number is determined solely by the number of protons, which does not change within isotopes of the same element.

Therefore, the true statement about x and y, which are isotopes, is that they have the same number of protons, aligning with option 4 in the question.