What are the colours and states of Group 7 elements at room temperature?

Group 7 elements, also known as halogens, range from pale yellow gas to black solid at room temperature.

Group 7 elements, known as the halogens, include fluorine, chlorine, bromine, iodine and astatine. Each of these elements has a distinct colour and state at room temperature.

Fluorine is a pale yellow gas. It's the most reactive of all the elements and can react with nearly every other element. Chlorine, the next halogen, is a greenish-yellow gas. It's less reactive than fluorine but still very reactive and is used in many industrial processes.

Bromine is unique among the halogens as it is a liquid at room temperature. It has a reddish-brown colour and gives off a similarly coloured vapour. Iodine, the next halogen, is a dark grey or purple solid at room temperature. When heated, it sublimates directly into a violet gas.

The final naturally occurring halogen, astatine, is a radioactive element and is usually not discussed in detail at GCSE level. However, it's worth noting that it's believed to be a black or dark purple solid at room temperature.

In summary, the halogens display a range of colours and states at room temperature, from pale yellow gas (fluorine) to greenish-yellow gas (chlorine), reddish-brown liquid (bromine), dark grey or purple solid (iodine), and black or dark purple solid (astatine). This variety is one of the many fascinating aspects of the Group 7 elements.