A single atoms mass cannot be weighted but can be compared to the mass spectrum.
Suppose we have element carbon , most of the mass of the atoms are compared to carbon
Ar the relative atomic mass , this is calculated as the avg mass of the atom
The different masses observed are the result of the presence of different numbers of neutrons in the nuclei of atoms of the same element. When this occurs, the atoms of the same element are called isotopes. This naturally exists in nature as there could be a lot of elementary transformations
Isotopes have the same atomic number but have different atomic masses
Calculation of isotopes And Atomic mass of elements
To measure the isotope , we will compare the mass of the atom to carbon-12 , lets say the mass of the atom is correctly 12 thus 1/12 into mass of one atom of carbon-12
Element Atomic symbol Relative atomic mass (Ar)
carbon C 12
hydrogen H 1
oxygen O 16
calcium Ca 40
copper Cu 64
gold Au 197
It is the number of electrons in an atom that determines the way in which it forms bonds and reacts with other atoms.
Some physical properties of the isotopes are different. The masses of the atoms differ and therefore other properties, such as density and rate of diffusion, also vary.
A visual illustration of how the presence of isotopes affects physical properties is the difference in density between ordinary ice and heavy-water ice (frozen deuterium oxide, D2O). Frozen deuterium oxide has a 10.6% greater density than ordinary ice.
Normal ice cubes float in water, but a heavy-water ice cube will sink
