Question

how are isotopes defined?
forms of different elements that have the same number of neutrons in each atom
forms of different elements that have the same number of protons in each atom
forms of the same element that differ in the number of neutrons in each atom
forms of the same element that differ in the number of protons in each atom

Explanation:

1. Recall the definition of isotopes: Isotopes are variants of a particular chemical element.
2. The key characteristic of isotopes is that they have the same number of protons (which defines the element) but a different number of neutrons.

• Option A is incorrect because isotopes are of the same element, not different elements, and they differ in neutrons, not have the same number of neutrons.
• Option B is incorrect as isotopes are of the same element, not different elements.
• Option D is incorrect because the number of protons defines the element, so isotopes of the same element must have the same number of protons and differ in neutrons.

So the correct answer is the option stating isotopes are forms of the same element that differ in the number of neutrons.

Answer:

C. forms of the same element that differ in the number of neutrons in each atom