Final answer:
Isotopes are variations of elements that have the same number of protons but different numbers of neutrons, leading to different mass numbers but similar physical and chemical properties due to identical electron configurations.
The correct option to describe isotopes is (b), which states, "Isotopes are elements with the same number of protons but different numbers of neutrons.
Step-by-step explanation:
Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons. The correct option to describe isotopes is (b), which states, "Isotopes are elements with the same number of protons but different numbers of neutrons.
Similar chemistries result from identical electron configurations." This means that the chemical behavior of isotopes is generally the same because they have the same electron configuration; it's the number of electrons around the nucleus that determines an element's chemical properties.
The difference in the number of neutrons between isotopes results in different mass numbers, but does not affect the chemistry of the element.
For example, hydrogen has three isotopes: normal hydrogen, deuterium, and tritium, which contain zero, one, and two neutrons respectively. All forms of hydrogen will react chemically in the same way because they have the same number of protons and electrons.
Therefore, isotopes of an element share the same physical and chemical properties despite having different atomic masses, which is the sum of the protons and neutrons in the nucleus. Understanding isotopes is also crucial when studying nuclear reactions and radioactive decay, where some isotopes are more stable than others.