1. Interpret Statement 1

For light stable nuclei, the number of neutrons $N$ is approximately equal to the number of protons $Z$. So, for small atomic number, $N \approx Z$ which means a plot of atomic number $Z$ (y-axis) versus number of neutrons $N$ (x-axis) lies close to the line $Z = N$ This is a straight line of $45^\circ$ slope.

For heavier stable nuclei, extra neutrons are needed for stability, so: $N > Z$ Hence, on a graph of $Z$ vs $N$, the points lie below the line $Z=N$ as $N$ increases. Therefore, the stable-nuclei curve bends away from the $45^\circ$ line towards the x-axis.

So, Statement 1 is true.

2. Interpret Statement 2

Inside the nucleus:

• Protons and neutrons are held together by strong nuclear forces.
• But protons also repel each other due to electrostatic repulsion.

As atomic number $Z$ increases, the number of proton-proton pairs increases, so Coulomb repulsion becomes more significant. To maintain stability, more neutrons are required because neutrons contribute to nuclear attraction without adding electrostatic repulsion.

Thus, for heavier nuclides, proton-proton repulsions increasingly overcome or compete against the attractive interactions, requiring excess neutrons.

So, Statement 2 is true.

3. Check whether Statement 2 explains Statement 1

Because heavier nuclei have larger proton-proton repulsion, they require more neutrons than protons for stability. That is why the stable nuclei no longer satisfy $N \approx Z$ and instead have $N > Z$ So in the plot of $Z$ vs $N$, the curve bends toward the x-axis as atomic number increases.

Therefore, Statement 2 correctly explains Statement 1.

4. Evaluate options

• A: Both statements are true, and Statement 2 is the correct explanation of Statement 1. ✅
• B: Explanation part is wrong. ❌
• C: Statement 2 is not false. ❌
• D: Statement 1 is not false. ❌

5. Final Answer

The correct option is: $\boxed{\text{A}}$

6. Comparison with stored answer

Stored correct answer: A

My derived answer: A

They agree.