Specification Point 2.5:
Know the colours, physical states (at room temperature) and trends in physical properties of these elements
The Physical Properties of Halogens
Halogens: Group 7 non-metals that are poisonous and includes: Fluorine, Chlorine, Bromine, Iodine and Astatine.
Halogens are diatomic, meaning they form molecules of two atoms.
Colours and States at Room Temperature:
Trends in Physical Properties:
- Melting Point
The Melting and Boiling Points of Halogens increases as you go down the group
Melting and boiling points of Halogens
- State at Room Temperature
- At room temperature (20 °C), the physical states of the Halogens become more hard and set.
- Chlorine is a gas, bromine is a liquid and iodine is a solid.
States of Halogens
- The Halogens become darker as you go down the group.
- Chlorine is pale green, bromine is red-brown and iodine is black.
Colours of Halogens
Specification Point 2.6:
Use knowledge of trends in Group 7 to predict the properties of other Halogens
Predicting the Properties of Halogens
Properties of other Halogens (Fluorine and Astatine):
Melting and Boiling Point
- The melting and boiling point of Halogens increases as you go down the group
- Fluorine is on the top of Group 7 so will have the lowest melting and boiling point
- Astatine is on the bottom of Group 7 so will have the highest melting and boiling point
- The states of Halogens become more hard and set as you go down the group
- Fluorine is on the top of Group 7 so will be a Gas
- Astatine is on the bottom of Group 7 so will be a Solid
- The colour of Halogens become darker as you go down the group
- Fluorine is on the top of Group 7 so the colour will be lighter: Yellow
- Astatine is on the bottom of Group 7 so the colour will be darker: Black
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Jamie got a First class degree in Chemistry from Oxford University before going on to teach chemistry full time as a professional tutor. He’s put together these handy revision notes to match the Edexcel IGCSE Chemistry specification so you can learn exactly what you need to know for your exams.
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