Explain what the term nucleon number means.
Bromine occurs naturally as a mixture of two stable isotopes, $^{79}\text{Br}$ and $^{81}\text{Br}$, with relative isotopic masses of $78.92$ and $80.92$ respectively.
Define what is meant by relative isotopic mass.
Using bromine’s relative atomic mass of $79.90$, calculate the relative isotopic abundances of $^{79}\text{Br}$ and $^{81}\text{Br}$.
Bromine reacts with element A to make a compound with empirical formula $\text{ABr}_3$. By mass, $\text{ABr}_3$ contains A, $4.31$; Br, $95.69$. Calculate the relative atomic mass, $A_r$, of A, and give your answer to three significant figures.
The elements in Period $3$ of the Periodic Table display different behaviours when they react with oxygen.
Describe the observations you would make when separate samples of magnesium and sulfur are reacted with oxygen. Write an equation for each reaction.
Write equations for the reactions of aluminium oxide, $\text{Al}_2\text{O}_3$, with sodium hydroxide and hydrochloric acid.
Phosphorus reacts with chlorine to form $\text{PCl}_5$. State the shape of a $\text{PCl}_5$ molecule and give two different bond angles.