What is an isotope?(3 points) Responses Two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei. Two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei. The time required for half of the atoms of a radioactive substance to break down into other elements. The time required for half of the atoms of a radioactive substance to break down into other elements. The geologic age of a fossil, or a geologic event or structure expressed in units of time, usually years. Also known as actual age.

Answer 1

An isotope is:

1. Definition: Two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei.
2. Characteristics: Isotopes of an element exhibit similar chemical properties because they have the same number of electrons, which determines chemical behavior, but they vary in mass due to the different numbers of neutrons.
3. Types: Isotopes can be stable or unstable (radioactive), where unstable isotopes decay over time into other elements, characterized by a specific half-life.

The other statements you provided, such as the definitions of half-life and geological age of fossils, do not pertain to the definition of an isotope.