Question

Atomic mass of an element is ________ .
[a] 1/12th the mass of a chlorine atom.
[b] 1/12th the mass of an oxygen atom
[c] 1/12th the mass of a C-12 isotope of carbon atom
[d] 1/12th the mass of an H-atom

Answer 1

[c] 1/12th the mass of a C-12 isotope of carbon atom

Explanation:

• The atomic mass of any element is the mass of one-twelfth the mass of an atom of carbon 12th.
• Atomic mass is expressed in relation to the carbon-12 standard.

     

Answer 2

Answer:

The atomic mass of an element is 1/12th the mass of a C-12 isotope of carbon atom

Explanation:

The atomic mass of an element is reported on a relative scale as it is difficult to find the exact mass of a very small particle. . ¹²C, one of the isotopes of carbon is taken as a standard value. All the atomic masses of the elements are determined relative to ¹²C.  one atom of ¹²C weighs 12 amu. One atomic mass unit is defined as one-twelfth of the mass of one  ¹²C atom.