PROPERTIES OF GROUP 17 ELEMENTS

Physical Properties of halogens

1. Are poisonous
2. Brittle and crumbly in their solid form
3. Do not conduct electricity
4. Form diatomic molecules (containing two atoms). For example Fl2.
5. Form colored vapors.

 Chemical Properties of halogens

1. The halogens are among the most reactive elements in the Periodic Table.
2. They all have seven valence electrons – seven electrons in their outer-shell.
3. They react with metals to form compounds called halides.

Reactivity increases as you go up Group 17

When halogens react with metals, the halogen atoms gain an electron. The smaller the atom the easier it is to attract the electron and the more reactive the element. (This is opposite of the trend in Group 1 where the larger the atom the easier it is to lose an electron.)