Identify the occupied orbital with the highest energy in a calcium atom. Sketch the shape of that orbital. Identify the highest-energy orbital in Ca. State the shape.
Write the equation that shows the thermal decomposition of calcium nitrate.
Suggest which of the Group 2 nitrates, calcium, magnesium or radium, needs the highest temperature for decomposition. Explain your answer.
Predict what you would observe when aqueous radium chloride is mixed with aqueous sodium sulfate. Do not mention temperature changes in your answer.
$^{25}_{12}\text{Mg}$ is an isotope of magnesium. Determine the numbers of protons and neutrons in an atom of $^{25}_{12}\text{Mg}$.
State the complete electronic configuration of an atom of $^{25}_{12}\text{Mg}$.
The relative atomic mass, $A_r$, is found by comparing the average mass of an element’s isotopes with the unified atomic mass unit. Define the unified atomic mass unit.
Calculate the mass of X. Use the data in Table 1.1 and $A_r(\text{magnesium}) = 24.31$ in your calculation. Show your working.
State one similarity and one difference in the properties of these isotopes of magnesium. Explain your answer.
Magnesium, Mg, burns in oxygen, $\text{O}_2$. The activation energy, $E_a$, for this reaction is $+148\,\text{kJ mol}^{-1}$. State one observation you would make when magnesium burns in oxygen. Do not mention temperature changes in your answer.
On Fig. 1.1, sketch a reaction pathway diagram for the reaction of Mg with $\text{O}_2$, and label the diagram to show the enthalpy change, $\Delta H$, and the activation energy, $E_a$, for the reaction.
Cold water reacts slowly with a piece of Mg to produce bubbles of $\text{H}_2(g)$. Cold water reacts rapidly with burning Mg to produce $\text{H}_2(g)$ in an explosive mixture. $\text{Mg} + 2\text{H}_2\text{O} \rightarrow \text{Mg(OH)}_2 + \text{H}_2$ Explain why the rate of reaction of cold water with burning magnesium is greater.