All isotopes of the same element have ______________ A. Different atomic numbers and different atomic mass B. Different atomic numbers and the same atomic mass C. The same atomic number but different atomic masses D. The same atomic number and the atomic mass

The correct answer is: C. The same atomic number but different atomic masses.

Isotopes are atoms of the same element that have different numbers of neutrons in their nuclei. The number of protons in the nucleus determines the element’s atomic number, which is the number that appears on the periodic table. The number of neutrons plus the number of protons equals the atom’s mass number. Isotopes of the same element have the same atomic number but different mass numbers.

For example, carbon-12 has 6 protons and 6 neutrons, while carbon-14 has 6 protons and 8 neutrons. Both carbon-12 and carbon-14 are isotopes of carbon, but they have different mass numbers.

Isotopes are important because they can be used to trace the movement of elements through the environment. For example, carbon-14 is used to date archaeological artifacts.