Question

Which of the following isotopes is used as the standard for atomic mass?

• A. ${}_6^{12}C$
• B. ${}_6^{14}C$
• C. ${}_8^{16}C$
• D. ${}_7^{14}C$

Answer 1

The correct option is A ${}_6^{12}C$

Atomic mass of an atom depends on the relative abundance of its isotopes. In case of carbon, the $C-12$ is used as the seal for atomic mass. A atomic mass is defines as the number of times of $1/{12}^{th}$ of the mass of $C-12$ atom.

option A is correct