Atomic Mass: Atomic mass refers to the mass of an individual atom of an element. It is typically expressed in atomic mass units (u) or Daltons (Da). Atomic mass is determined by the sum of the masses of protons and neutrons in the atomic nucleus. Since electrons have a very small mass compared to protons and neutrons, they are typically not included when calculating atomic mass. Atomic mass is often represented by the symbol "m" or "M".
Atomic Weight: Atomic weight, also known as atomic mass (in the context of the periodic table), is the weighted average mass of all the naturally occurring isotopes of an element. Isotopes are atoms of the same element that have different numbers of neutrons, resulting in different mass numbers. Since isotopes occur in different abundances in nature, the atomic weight is calculated by taking into account the mass of each isotope and its relative abundance. Atomic weight is expressed in atomic mass units (u) or as a dimensionless value. Atomic weight is often represented by the symbol "A" or "Aw".
Atomic Number: Atomic number is a fundamental property of an element, denoted by the symbol "Z". It represents the number of protons in the nucleus of an atom, which defines the identity of the element. In a neutral atom, the atomic number also indicates the number of electrons surrounding the nucleus. Each element has a unique atomic number, and elements are arranged in ascending order of atomic number in the periodic table. The atomic number determines the element's position and properties in the periodic table.
To summarize, atomic mass refers to the mass of an individual atom, atomic weight is the weighted average mass of all the naturally occurring isotopes of an element, and atomic number represents the number of protons in an atom's nucleus and defines the element's identity.