💏intro to chemistry review

Halogens

Written by the Fiveable Content Team • Last updated August 2025
Written by the Fiveable Content Team • Last updated August 2025

Definition

Halogens are a group of elements in Group 17 of the periodic table known for their high reactivity and tendency to form salts with metals. They include fluorine, chlorine, bromine, iodine, and astatine.

AP course connection

Topic 7.1: 7.1 Ionic Bonding

Unit 7

5 Must Know Facts For Your Next Test

  1. Halogens have seven valence electrons, making them highly reactive.
  2. They readily form negative ions by gaining one electron to achieve a stable octet.
  3. Halogens exist in various physical states at room temperature: fluorine and chlorine are gases, bromine is a liquid, and iodine is a solid.
  4. They have high electronegativities and are strong oxidizing agents.
  5. Halogens form diatomic molecules (e.g., F2, Cl2) in their elemental state.

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