State which negative ion has the smallest mass in $1000\,\text{cm}^3$ of sea water.
Give the formulas of the ions in potassium sulfate.
Calculate the mass of calcium ions in $200\,\text{cm}^3$ of this sea water sample.
A sample of this sea water is evaporated. State the name of the compound that is present in the greatest amount after evaporation.
Give the name of the ion that reacts with aqueous silver nitrate to form a cream precipitate.
The $\text{B}_3\text{O}_6^{3-}$ ion can be changed into boric acid, H$_3$BO$_3$. Boric acid is also formed when boron trichloride, BCl$_3$, reacts with water. Complete the equation for this reaction. BCl$_3$ + ...H$_2$O $\rightarrow$ H$_3$BO$_3$ + ...HCl
The symbol for a strontium ion is shown: $^{87}_{38}\text{Sr}^{2+}$. Deduce how many electrons, protons and neutrons are in one ion of strontium.
Give one medical use of radioactive isotopes.
The isotope $^{235}$U is also radioactive. State the main use of this uranium isotope.