Group 7 Elements

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!

Halogens consist of molecules. Examples of halogens are Fl, Ch and Io. Halogens can dyes and kill in water. They are h because they are very reactive. These elements form salts when they combine with metals. Halogens become reactive as the group is descended.

Chlorine is a pale gas. It is smelly and poisonous. Bromine is a deep liquid with a red-brown . It is also smelly and poisonous. It occurs as . Magnesium is found in the sea.

Iodine is a grey with a vapour. It is smelly and poisonous. It occurs as iodides and in some rocks.

Halogen compounds are very useful . NaCl is turned into in the chemical industry. The chlorine is then used to make plastics such as . This plastic is used to make window frames, gutters, and pipes. Chlorine is also used to stop the spread of . There are problems with chlorine . Since they are so they can remain in the environment. Halogen compounds such as CFCs can break down the ozone layer. The ozone layer is useful in absorbing radiation from reaching Earth.This radiation is responsible for causing skin

Most of the bromine originates from the . It has a useful application in photography, since it is used in photographic . Liquid bromine is also used for drugs used in , and in to prevent crop damage.

The human body needs small quantities of iodine to remain . If the body does not receive enough iodine then disease of the can occur. Iodine is also used for the manufacture of medicines, dyes and for chemicals used in .