MCQ Detailed View

Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons in the nucleus. Because the number of protons is the same, isotopes have the same electronic configuration and occupy the same position in the periodic table. This means their chemical properties, which depend on electron arrangements, are largely identical.

The main difference between isotopes lies in mass-dependent properties. Since the neutron number changes, the atomic mass varies between isotopes. This affects properties such as density, melting point, boiling point, rate of diffusion, and physical stability. For example, hydrogen has three isotopes: protium (¹H), deuterium (²H), and tritium (³H). All three have the same chemical behavior but differ in mass, leading to differences in physical properties.

Isotopic differences are also important in nuclear chemistry. Some isotopes are radioactive while others are stable. The variation in neutron number influences the nuclear stability, decay patterns, and applications in medicine, radiometric dating, and tracer studies.

Properties that depend on mass are called physical properties, whereas chemical properties remain nearly identical for isotopes. This distinction is fundamental in understanding why isotopes are chemically similar but physically distinguishable.

In summary, isotopes of an element differ in properties that depend on mass because of the variation in neutron numbers, while their electron arrangements, chemical behavior, and periodic table positions remain the same.