Question
2 Bromine reacts with iron to form iron(III) bromide. (a) (i) Identify the structure of iron (Vert vert ) bromide. A giant ionic B giant metallic C giant molecular D simple molecular (ii) Add numbers to balance the equation for the reaction between iron and bromine. (1) ldots ldots Fe+ldots ldots Br_(2)arrow 2FeBr_(3) (b) Bromine and gallium are in period 4 of the periodic table. The electronegativity of the elements in period 4 changes across the period. Explain how the electronegativity changes from gallium to bromine. (4) (1)
Answer
4.3
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Xanthe
Elite · Tutor for 8 years
Answer
(a)(i) A (ii) Fe coefficient is 2 and Br coefficient is 3.(b) Electronegativity increases from gallium to bromine across the fourth period as you move from left to right across period 4 in the periodic table, electronegativity increases, due to the increase of protons in the nucleus and thus ionic charge increases. Thus, the electron cloud adjusts to this higher charge, which is why gallium, located on the left side, has lower electronegativity when compared to bromine, located on the right side of the periodic table.
Explanation
(a)(i) Iron(III) bromide taken as FeBr3 indicates an ionic compound formed from the transfer of electrons from Iron to Bromine. Thus, causing electroneutrality between an Iron cation and Bromine anion which implies that the structure is giant ionic.(ii) In the given reaction equation, 2 moles of Fe individually react with 3 moles of Br2 (since Bromine exists as molecules of Br2 under normal conditions), to yield 2 moles of FeBr3 in order to balance the law of conservation of it. So the missing coefficients would be 2 for Fe and 3 for Br2. (b) Period 4 of the periodic table starts with potassium (K) and ends with krypton (Kr). Gallium (Ga) is in group 13th and Bromine (Br) is in group 17. Electronegativity generally increases from left to right across a period, so we expect the electronegativity to increase from gallium to bromine.