Explain why the first ionisation energies decrease down the group.
Explain why, for each element, there is a large jump between the 2nd and 3rd ionisation energies.
Write the full electronic configuration of strontium. $1s^2\ 2s^2\ 2p^6\ \ldots$
Explain why the mass spectrum of strontium has four separate peaks.
Calculate the atomic mass, $A_r$, for this sample of strontium. Give your answer correct to three significant figures.
Explain, using electron transfer, what the term oxidising agent means.
The percentage composition by mass of $A$ is Ba, $45.1$; Cl, $23.4$; O, $31.5$. Calculate the empirical formula for $A$.
State the formulae of the compounds $X$, $Y$ and $Z$.
State the reagent required to turn $Y(s)$ into $Z(aq)$ in reaction $1$, and write an equation for the reaction.
How would you convert a sample of $Z(s)$ to $Y(s)$ in reaction $2$?
Write equations for the conversions of Mg into $X$, and $Z(s)$ into $Y$. Mg to $X$. $Z$ to $Y$.