6) Group 7

• The Group 7 elements are non-metals and are known as the halogens
• They have seven electrons in their outermost shell.
•  Reactivity decreases down the group because the outer shell gets further away from the nucleus, so it is less easy to gain an electron.
• Halogens react with metals to produce ionic salts.

  When this happens, the halogen atom gains one electron to form a halide ion with a negative charge (-1).
• A more reactive halogen will displace a less reactive halogen from an aqueous solution of its salt.