Chapter 2, Problem 1QAP

To determine

The difference between atomic mass and atomic weight

Explanation of Solution

Write the difference between atomic mass and atomic weight in tabular form.

S. no	Atomic mass	Atomic weight
1	It is defined as adding the number of protons and neutrons in atom.	It is defined as average weight of an element, with respect to all isotopes and their abundance.
2	One atomic mass unit (amu) is the one twelfth of the mass of the C-12 isotope.	Ratio of the average mass per atom of the element to 1/12 of the mass of atom of C-12.
3	Expression of atomic mass. $A\cong Z+N$ Here, A is for atomic mass, Z is for atomic number and N is for neutrons.	Expression for atomic weight of element. ${\overline{A}}_{\text{M}}=\underset{i}{\Sigma }{f}_{i_{\text{M}}}{A}_{i_{\text{M}}}$ Here, M is for an element, ${\overline{A}}_{\text{M}}$ is for fraction-of-occurrence-atomic weight, $A_{i_{\text{M}}}$ is for atomic weight of the isotope, $f_{i_{\text{M}}}$ is for fraction-of-occurrence of isotope $\left(i\right)$ for element.