Question

The value of atomic mass of carbon in periodic table is 12.011 a.m.u,rather than 12.00 a.m.u? explain

Answer 1

Explanation:

The mass of Carbon-12 is exactly 12 amu. But, that is not the number that is reported in your periodic table. Carbon as it exists in nature is not all carbon-12. There is some small amount of carbon-13 and even traces of carbon-14 in there. The periodic table reports the average mass of the carbon as it is found in nature, not that of pure carbon-12. The average mass of carbon is slightly heaver than carbon-12, because of the slight amounts of those heaver isotopes of carbon in nature,

Answer 2

Answer:

The masses on the periodic table represent the average mass of all isotopes discovered in the universe, as well as their abundances.

This is why the atomic mass of carbon is periodic table is $12.011$ amu.

Explanation:

Atomic mass :

The atomic mass listed in the periodic table is a weighted average based on each element's relative abundance.

Relative abundance :

The term "relative abundance" describes how common an isotope is in nature.

Although carbon$-12$ weighs exactly $12$ amu, the periodic table gives a mass of $12.011$because the abundances and masses of the other two carbon isotopes (carbon $13$ and carbon $14$) are taken into account.