Fundamentals of Atomic Mass

Dalton's Atomic Theory

• Dalton's Atomic theory proposes that each element has a distinguishing atomic mass.

• This concept allows for the explanation of the Law of Constant Proportions.

Relative Atomic Mass Determination

• Due to the small size of atoms, direct mass evaluation is difficult.

• Scientists evaluate mass relatively by comparing an atom to a standard reference.

Standards and Definition

• Definition: Atomic mass is the number of times an atom of an element is heavier than $\frac{1}{12}$ of a carbon atom.

• Evolution of Standards: Carbon is the current international standard for calculating atomic mass; Oxygen was used as the standard element earlier.

• Example: Sodium ($23$) is $23$ times heavier than $\frac{1}{12}$ of a carbon atom.