C3e Group 7 Element Answer PDF

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Item C3e: The Group 7 Elements 1. Elements in group 7 are called halogens 2. The elements in this group have 7 electrons on their outer shells. 3. Fluorine, Chlorine, bromine and iodine are all examples of halogens. 4. State the uses of these halogens:  chlorine to sterilise water;  chlorine is also used to make pesticides and plastics;  iodine is used to sterilise wounds.

5. State that sodium chloride is used:  as a preservative;  as a flavouring;  to manufacture chlorine.

6. Halogens react with alkali metals and produce metal halides. For example, chlorine reacts with sodium to produce sodium chloride. 7. Write a word equation for the above chemical reaction: 8. Complete the following chemical reactions: i)

sodium + fluorine  Sodium fluoride

ii)

Potassium + iodine  Potassium iodide

iii)

Lithium + chlorine  lithium chloride

9. Match of the following halogens to their descriptions:

Halogen

Description

Chlorine

Orange- red liquid

Bromine

Gray solid

Iodine

Pale yellow toxic gas

10. Rewrite the following halogens, in the order of reactivity. Lowest firstchlorine, fluorine, bromine and iodine. Iodine

bromine

chlorine

fluorine

Lowest reactivity

Highest reactivity

11. Displacement reactions: i) ii)

chlorine displaces bromides and iodides; bromine displaces iodides.

12. If you add chlorine to the following compounds, in a test tube, what will you observe? i)

potassium iodide- purple colour; iodine gets displaced

ii)

Potassium bromide- orange, bromine gets displaced

iii)

Write two word equations to describe the above two reactions

13. All the halogens have similar chemical properties, because they all have 7 outer shell electrons....