- published: 09 Oct 2012
- views: 137506
The atomic mass (ma) is the mass of an atomic particle, sub-atomic particle, or molecule. It is commonly expressed in unified atomic mass units (u) where by international agreement, 1 unified atomic mass unit is defined as 1/12 of the mass of a single carbon-12 atom (at rest). For atoms, the protons and neutrons of the nucleus account for almost all of the mass, and the atomic mass measured in u has nearly the same value as the mass number.
When divided by unified atomic mass units or daltons to form a pure number ratio, the atomic mass of an atom becomes a dimensionless number called the relative isotopic mass (see section below). Thus, the atomic mass of a carbon-12 atom is 12 u or 12 daltons (Da), but the relative isotopic mass of a carbon-12 atom is simply 12.
Atomic Mass: Introduction
Atomic Mass
Atomic weight and atomic mass | Atoms, compounds, and ions | Chemistry | Khan Academy
What's the Difference between Mass Number and Atomic Mass?
Atomic Number and Mass Number | Chemistry | Fuse School
Atomic Mass of an Atom - Chemistry Class IX CBSE, ICSE, NCERT
In Depth: Atomic Mass Units | Chemistry for All | The Fuse School
What is Relative Atomic Mass? | Chemistry | The Fuse School
How to Calculate Atomic Mass Practice Problems
Chemistry: Average Atomic Mass (amu, Daltons, etc.) - 2 examples | Homework Tutor