Some about Atomic weight

Atomic weight
The atomic weight of an element is defined as the average weight of the atoms of the element relative to a carbon atom, taken as exactly 12. Atomic weight in grams is, in fact, the weight of one mole of atoms, e.g., the atomic weight of oxygen is 16 and so 16 grams is the weight of 1 mole of oxygen atoms.
Mathematically,
atomic weight = weight of atoms in grams/number of moles of atoms
Atomic weight is measured in atomic mass unit. Atomic mass unit is defined as 1/12 of the mass of the C isotope. One amu is also called one dalton.