Answer
See the detailed answer below.
Work Step by Step
$$\color{blue}{\bf [a]}$$
To create an energy-level diagram for all $ A = 10 $ nuclei, we need to show the distribution of protons and neutrons. The common $ A = 10 $ isobars are:
$$\text{Beryllium ($ ^{10}\text{Be} $),$\quad$ Boron ($ ^{10} \text{B} $), $\quad$ Carbon ($^{10}\text{C}$) } $$
1. Beryllium ($^ {10}\text{Be}$): It has 4 protons and 6 neutrons.
2. Boron ($^ {10}\text{B}$): It has 5 protons and 5 neutrons.
3. Carbon ($^{10}\text{C}$) It has 6 protons and 4 neutrons.
See the graphs below.
$$\color{blue}{\bf [b]}$$
1. Boron-10 ($^ {10}\text{B}$) is stable.
2. Beryllium-10 ($^ {10}\text{Be}$) is radioactive and undergoes beta-minus ($ \beta^- $) decay.
3. Carbon-10 ($^{10}\text{C}$) is radioactive and undergoes beta-plus ($ \beta^+ $) decay due to its proton-rich configuration.
Now we have covered the $ A = 10 $ nuclei: Beryllium-10, Boron-10, and Carbon-10. Only $\underline{\color{red}{\text{ Boron-10 is stable }}}$ among these isotopes.
