Explain the meaning of isobars, giving an example.

What are the changes in the mass number $A$ and atomic number $Z$ of a nucleus due to radioactive disintegration?

Does the neutron to proton ratio in a nucleus increase, decrease or remain same after the nucleus emits an $\alpha$-particle?

Write down the number of protons, electrons and neutrons in the following atoms:${}_2{\mathrm{He}}^3$.

Write down the number of protons, electrons and neutrons in the following atoms: ${}_6\mathrm{C}^{13}$.

Write down the number of protons, electrons and neutrons in the following atoms:${}_7{\mathrm{N}}^{13}$