Difference Between Atomic Weight and Atomic Mass

Atomic mass and atomic weight do not mean the same but still some people use the terms interchangeably. To make you understand how atomic mass and atomic weight are different from each other, some major differences between atomic mass and atomic weight mentioned below:

Atomic Mass

• It is the sum of neutrons and protons present in an atom
• Isotopes are not included in the calculation
• Calculated value is a whole number
• Analysis is done by mass spectroscopy

Atomic Weight

• Average of ratio of atoms, present in an element
• Isotopes are included in the calculation
• Calculated value may or may not be a whole number
• Analysis is done by mass spectroscopy