The elements in Group 7, commonly referred to as the halogens, exhibit a diverse range of colors and physical states at room temperature, spanning from pale yellow gases to black solids.

The halogens include five distinct elements: fluorine, chlorine, bromine, iodine, and astatine. Each of these elements possesses unique characteristics in terms of color and physical state.

Fluorine is a pale yellow gas and holds the title of the most reactive element, capable of reacting with nearly all other elements. Following fluorine in the group is chlorine, which appears as a greenish-yellow gas. While chlorine is somewhat less reactive than fluorine, it remains highly reactive and plays a significant role in various industrial applications.

Bromine stands out among the halogens as it is a liquid at room temperature, exhibiting a reddish-brown hue and releasing a similarly colored vapor. Iodine, the next element in the group, exists as a dark grey or purple solid at room temperature. When heated, iodine sublimes directly into a violet gas.

The final naturally occurring halogen, astatine, is a radioactive element that is typically not covered in detail at the GCSE level. Nevertheless, it is believed to be a black or dark purple solid at room temperature.

In summary, the halogens present a fascinating array of colors and states at room temperature: from pale yellow gas ($\text{F}_2$) for fluorine, to greenish-yellow gas ($\text{Cl}_2$) for chlorine, reddish-brown liquid ($\text{Br}_2$) for bromine, dark grey or purple solid ($\text{I}_2$) for iodine, and finally, black or dark purple solid for astatine. This remarkable variety is one of the many intriguing features of the Group 7 elements.