Complete the word equation to show the halogen and halide compound which react to form the products iodine and potassium bromide.
Explain, in terms of the reactivity of the halogens, why aqueous iodine does not react with aqueous potassium chloride.
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Complete the word equation to show the halogen and halide compound which react to form the products bromine and potassium chloride.
Explain, in terms of the reactivity of the halogens, why aqueous bromine will not react with aqueous potassium chloride.
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The halogens are a collection of diatomic non-metals in Group VII.
| halogen |
solid, liquid or gas at room temperature |
colour |
| chlorine | ||
| bromine | ||
| iodine |
[2]
The halogens react with other non-metals to form covalent compounds.
Draw a diagram which shows the arrangement of the valency electrons in one molecule of the covalent compound arsenic trifluoride.
The electron distribution of an arsenic atom is 2 + 8 + 18 + 5.
Use x to represent an electron from an arsenic atom.
Use o to represent an electron from a fluorine atom.
Photochromic glass is used in sunglasses. In bright light, the glass darkens reducing the amount of light reaching the eye. When the light is less bright, the glass becomes colourless increasing the amount of light reaching the eye.
Photochromic glass contains very small amounts of the halides silver(I) chloride and copper(I) chloride.
The reaction between these two chlorides is photochemical.
| AgCl | + | CuCl | format('truetype')%3Bfont-weight%3Anormal%3Bfont-style%3Anormal%3B%7D%3C%2Fstyle%3E%3C%2Fdefs%3E%3Ctext%20font-family%3D%22math1aa495e18c7e3a21a4e48923b92%22%20font-size%3D%2216%22%20text-anchor%3D%22middle%22%20x%3D%2210.5%22%20y%3D%2216%22%3E%26%23x21CC%3B%3C%2Ftext%3E%3C%2Fsvg%3E) |
Ag | + | CuCl2 |
| colourless | colourless | black | colourless |
How does photochromic glass work?
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Three of the halogens in Group VII are:
chlorine
bromine
iodine
Describe how you could distinguish between aqueous potassium bromide and aqueous potassium iodide.
Test ....................
Result with bromide ............................................................
Result with iodide ............................................................
0.015 moles of iodine react with 0.045 moles of chlorine to form 0.030 moles of a single product.
Complete the equation.
I2 + ............ Cl2 → ................................
Traces of chlorine can be separated from bromine vapour by diffusion.
Which gas would diffuse the faster and why?
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Three of the halogens in Group VII are listed below.
| chlorine |
| bromine |
| iodine |
5 marksA radioactive isotope of iodine, 
, is used to treat cancer.
How many protons, electrons and neutrons are there in one atom of
number of protons ..............
number of electrons ............
number of neutrons ............
[2]
When this isotope, , emits radiation, a different element with a proton number of 54 is formed.
What is the name of this element?
[1]
2 marksFluorine, the most reactive halogen, forms compounds with the other halogens. It forms two compounds with bromine.
Deduce their formulae from the following information.
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Table 1 shows some properties of some of the halogens.
Table 1
Use the information in Table 1 to suggest:
• the colour of astatine ______________
• the boiling point of bromine ____________
• the state of iodine at 190 °C _______________
Aqueous chlorine reacts with aqueous potassium bromide as shown.
Cl2 + 2KBr → Br2 + 2KCl
Name the salt formed in this reaction.
Explain why aqueous bromine does not react with aqueous potassium chloride.
Complete the dot-and-cross diagram in Figure 1 of a molecule of chlorine.
Show outer shell electrons only.
Figure 1
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