* Isotopes: The atomic mass listed on the periodic table is the average atomic mass, taking into account the abundance of all naturally occurring isotopes of that element. Isotopes are atoms of the same element that have different numbers of neutrons, and therefore different atomic masses. For example, carbon has two main isotopes: carbon-12 (with 6 neutrons) and carbon-14 (with 8 neutrons). The atomic mass of carbon on the periodic table is 12.011 amu, reflecting the relative abundance of these isotopes.
* Nuclear Reactions: Atomic mass can change during nuclear reactions, such as nuclear fission or fusion. These reactions involve changes in the nucleus of an atom, which can result in the creation of new elements with different atomic masses.
* Radioactive Decay: Certain isotopes of an element are radioactive and undergo radioactive decay, which can change the atomic mass. For example, carbon-14 decays into nitrogen-14, changing the atomic mass of the atom.
However, the atomic mass of an individual atom of a specific isotope is fixed. For example, a carbon-12 atom will always have an atomic mass of 12 amu, and a carbon-14 atom will always have an atomic mass of 14 amu.
Therefore, the atomic mass of a particular element can change on a macroscopic level due to the presence of different isotopes or nuclear reactions. However, the atomic mass of an individual atom of a specific isotope is fixed.
