different between atomic nd atomic mass
Answers
Answer:
Atomic mass is also has atomic weight.Atomic mass is the weighted average mass of an atom of an element based on the relative neutral abundance of that element's isotopes.The mass number is a count of the total number of protons and neutrons in an atom's nucleus.
Explanation:
Answer:
The mass number is the number of nucleons (protons and neutrons) in the nucleus of an atom.
For example 126C has a mass number of 12 as it has 6 protons and 6 neutrons in its nucleus and 3517Cl has a mass number of 35 as it has 17 protons and 18 neutrons in its nucleus.
The atomic mass of an atom is the mass of the atom in atomic mass units (amu or u).
The atomic mass of a 126C atom is defined as being 12 atomic mass units.
The atomic mass of a 3517Cl atom is 34.96885268 atomic mass units ie a 3517Cl atom is 34.9688526812 heavier than a 126C atom.
Note that the atomic mass is approximately equal to the mass number.
There is a third quantity which you should be aware of which is used by Chemists and that is the (standard) atomic weight.
The unit is again the atomic mass unit but it is the average atomic mass of the different types of atoms (isotppes) of which an element is composed.
For example in nature carbon exists as the isotopes 126C,136C and 146C and so you will see the atomic weight of carbon listed as 12.011 to reflect the fact that natural carbon is 75%126C,24%136C with a trace of 146C.
However the isotopic composition of Carbon may vary and so you will also see the standard atomic weight listed as a range of values such as [12.009612.0116] when greater accuracy is required.