Physical properties of the group 7 elements
The vertical column of non-metal elements next to group 0 in the periodic table, also called the halogens. contains Element that is a poor conductor of electricity and heat, and which forms acidic oxides.A substance made of one type of atom only. placed in a vertical column on the right of the periodic table. The elements in group 7 are called the An element placed in group 7 of the periodic table, which starts with fluorine and ends with astatine. The name 'halogen' means 'salt-producing' because halogens produce a range of salts when they react with metals..
The halogens show trends in their A description of the appearance of a substance or how it acts without involving chemical reactions. For example, state, melting point, conductivity, etc. and A description of how a substance reacts with other substances. For example, flammability, pH, reaction with acid, etc..
Physical properties
The table shows the colour and physical Solid, liquid or gas. Evaporation is a change of state from liquid to gas. of chlorine, bromine and iodine at room temperature and pressure.
| Group 7 element | Colour | State | Colour in gas state |
| Chlorine, Cl2 | Yellow-green | Gas | Yellow-green |
| Bromine, Br2 | Deep-red | Liquid | Red-brown |
| Iodine, I2 | Grey | Solid | Purple |
| Group 7 element | Chlorine, Cl2 |
|---|---|
| Colour | Yellow-green |
| State | Gas |
| Colour in gas state | Yellow-green |
| Group 7 element | Bromine, Br2 |
|---|---|
| Colour | Deep-red |
| State | Liquid |
| Colour in gas state | Red-brown |
| Group 7 element | Iodine, I2 |
|---|---|
| Colour | Grey |
| State | Solid |
| Colour in gas state | Purple |
The The temperature at which a solid changes into a liquid as it is heated. and The temperature at which a substance rapidly changes from a liquid to a gas. of the halogens increase going down group 7, and their colour gets darker.
The group 7 elements exist as A molecule made up of only two atoms. The seven diatomic elements are iodine, bromine, chlorine, fluorine, oxygen, nitrogen and hydrogen.A collection of two or more atoms held together by chemical bonds.. Their chemical formulae are F2, Cl2, Br2 and I2.
The bond between the The smallest part of an element that can exist. in a molecule is very strong, but the forces of attraction between molecules are weak. This explains why group 7 elements have low boiling points.
Question
The graph shows the melting and boiling points of the first four group 7 elements. Astatine is placed below iodine in group 7. Predict the melting and boiling points of astatine, and its state at room temperature.
Astatine should have a melting point of about 300°C and a boiling point of about 340°C. This means that it will be solid at room temperature. (Actual boiling point is 350°C.)
