Chapter 40, Problem 20A

To determine

The primary difference in the graphs.

Explanation of Solution

Introduction:

The given graphs are drawn between the mass and atomic number. The atomic number of atom is shown along horizontal axis and mass on the vertical axis.

The graph of figure 40.13 shows the relationship between the mass of the nucleus with its atomic number. The mass of the nucleus of atom increases with the atomic number of the atom, so the slope of the figure 40.13 increases with atomic number.

The graph of figure 40.14 shows the relationship between the mass per nucleon and atomic number. The mass per nucleon decrease with increase in atomic number, so the slope of graph in figure 40.14 decreases. The slope of graph in figure 40.14 is minimum for heaviest atom and maximum for lightest atom.

Conclusion:

Thus, the slope of graph in figure 40.13 increases with increase in atomic number but the slope of graph in figures 40.14 decreases with increase in atomic number.