Chemistry 9701 · AS & A Level · The Periodic Table: chemical periodicity

The Periodic Table: chemical periodicity — practice question

The alkali metals make up six elements in Group I of the Periodic Table. Their first ionisation energy follows a clear pattern as the Group is descended.
(a)[2]

Define first ionisation energy.

(b(i))

State and explain how first ionisation energy changes as Group I is descended.

(b(ii))[3]

Suggest how this trend helps account for the rise in reactivity as the Group is descended.

(c(i))

In a redox reaction, $0.83\,\text{g}$ of lithium reacted with water to produce $0.50\,\text{dm}^3$ of aqueous lithium hydroxide according to the equation $2\text{Li}(s) + 2\text{H}_2\text{O}(l) \rightarrow 2\text{LiOH}(aq) + \text{H}_2(g)$. Calculate the amount, in moles, of lithium that reacted.

(c)

In a redox reaction, $0.83\text{ g}$ of lithium reacted with water to produce $0.50\text{ dm}^3$ of aqueous lithium hydroxide. $\text{2Li(s)} + \text{2H}_2\text{O(l)} \rightarrow \text{2LiOH(aq)} + \text{H}_2\text{(g)}$

(c(ii))

Calculate the volume of hydrogen formed at room temperature and pressure.

(c(iii))[5]

Calculate the concentration, in $\text{mol dm}^{-3}$, of the $\text{LiOH(aq)}$ produced.

(d)[2]

When heated in chlorine, every alkali metal reacts to make the corresponding chloride. Describe the observations when sodium is heated in chlorine and write a balanced equation for the reaction.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: energy needed to remove one electron from every atom in one mole of gaseous atoms

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