A dense, poisonous, dark grey crystalline solid or a purple vapour
Iodine
A dense, poisonous, violet-black solid that forms molecules
Trends in Group 7 elements
1. Going down the group, the halogens become less reactive as it is harder to gain an extra electron due to the outer shell being further from the nucleus
2. Have higher melting and boiling points
3. Have higher relative atomic masses
All the Group 7 elements react in similar ways because they all have seven electrons in their outer shell
Molecular compounds
Compounds formed when halogen atoms share electrons via covalent bonding to achieve a stable outer shell
