Complete Table 1.1 by giving the numbers of protons, neutrons and electrons for the two stable gallium isotopes, $^{69}\text{Ga}$ and $^{71}\text{Ga}$.
Define what is meant by relative atomic mass.
The relative atomic mass of gallium, $A_r$, is $69.723$. The relative isotopic masses of $^{69}\text{Ga}$ and $^{71}\text{Ga}$ are $68.926$ and $70.925$, respectively. Use these data to calculate the percentage abundance of $^{69}\text{Ga}$ in elemental gallium. Assume that only the $^{69}\text{Ga}$ and $^{71}\text{Ga}$ isotopes are present. Give your answer to four significant figures.
Explain why the two isotopes of potassium have the same chemical properties.
State the full electronic configuration of an atom of potassium.
The first, second and third ionisation energies of potassium are $418$, $3070$ and $4600\ \text{kJ mol}^{-1}$, respectively. Use this information to explain why potassium belongs in Group 1.