Halogens

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.

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.

Review Questions

• Which group in the periodic table do halogens belong to?
• What type of ions do halogens typically form?
• Name three physical states that halogens can exist in at room temperature.

Related terms

Electronegativity: A measure of an atom's ability to attract and hold onto electrons within a bond.

Oxidizing Agent: A substance that gains electrons during a chemical reaction and thereby gets reduced.

Diatomic Molecule: $\text{A molecule consisting of two atoms, which can be the same or different element. Examples: } O_2 \text{and} HCl$