Fill in the table by giving the ion symbol that matches the numbers of protons, electrons and neutrons listed in the table below. The first row has already been completed as an example.
Describe and explain how the solubilities of the sulfates of the Group II elements change down the group.
Calcium sulfate is only sparingly soluble in water. Describe and explain what would be observed if a few cm$^3$ of concentrated Na$_2$SO$_4$(aq) were introduced into a saturated solution of CaSO$_4$(aq).
A solution of a chromium salt $X$ is electrolysed, and chromium metal is deposited on the cathode according to the equation below. Cr$^{n+}$(aq) + $ne^-$ $\rightarrow$ Cr(s) If a current of 1.8 A was passed for 40 minutes through a solution of salt $X$, 0.776 g of chromium was deposited. Calculate the value of $n$ in the equation above. Show your working.