Question

what is the difference between atomic mass and mass number of an atom?

Answer 1

Atomic Mass	Mass number
1. Atomic mass is fractional because it is the average relative mass of its atoms as compared with the mass of an atom of C-12 isotope taken as 12.	1. Mass number is a whole number because it is the sum of the number of proton and the number of neutrons
2. Atomic mass is the weighted average mass of an atom of an element based on the relative natural abundance of that element's isotopes.	2. The mass number is a count of the total number of protons and neutrons in an atom's nucleus.
3. Atomic mass is included in all isotopes	3. Calculating mass number isotopes are not included.
4. Atomic mass is also used to classify different isotopes of the same element	4. Isotopes of the same element have different mass numbers.
5. Atomic mass is mostly measured using an atomic mass unit (amu).	5. It has no units.
6. Atomic mass is the same for one element	6. Mass number is different for elements having different isotopes.