Fluorine, chlorine, and bromine are elements in Group 7 of the Periodic Table.
State the number of outer-shell electrons in an atom of fluorine.
Identify an element in Group 7 that is a dark-grey solid at room temperature.
Identify an element in Group 7 that is more reactive than bromine.
Bromine is formed by the electrolysis of molten lead(II) bromide, PbBr2\text{PbBr}_2PbBr2. During this process, electrode A\text{A}A is the positive electrode (anode) and electrode B\text{B}B is the negative electrode (cathode).
Explain why solid lead(II) bromide does not conduct electricity, whereas molten lead(II) bromide does.
During electrolysis, brown fumes of bromine gas are observed at electrode A\text{A}A. The ionic half-equation for this reaction is:
2Br−→Br2+2e− 2\text{Br}^- \rightarrow \text{Br}_2 + 2\text{e}^- 2Br−→Br2+2e−Why is this reaction described as oxidation?
Write an ionic half-equation for the reaction at electrode B\text{B}B and describe the appearance of the product that forms on this electrode.
Sodium bromate is a compound containing sodium, bromine, and oxygen. A sample of sodium bromate is analyzed and found to contain 3.45 g3.45\text{ g}3.45 g of sodium, 11.985 g11.985\text{ g}11.985 g of bromine, and 7.2 g7.2\text{ g}7.2 g of oxygen. Calculate the empirical formula of this compound. [Relative atomic masses, ArA_rAr: Na=23\text{Na} = 23Na=23; Br=79.9\text{Br} = 79.9Br=79.9; O=16\text{O} = 16O=16]
