Determine the electron group arrangement around the central atom that minimizes repulsions. Assign an AXmEn designation; then identify the LP-LP, LP-BP, or BP-BP interactions and predict deviations from ideal bond angles. Describe the molecular geometry.
The group 7 halogens require to gain or share the least electrons to form an ion or molecule in which the halogen atom has a very stable noble gas electron arrangement. This requires the least energy, so the group 7 halogens tend to be the most reactive non-metals on the right-hand side of the periodic table.