3.2.2 Halogens

• The halogens are highly reactive nonmetal elements in the periodic table, including fluorine, chlorine, bromine, iodine, and astatine
• The most reactive halogen is fluorine
• Arrange the trends in halogen properties as you move down Period 7:

  1️⃣ Decreasing reactivity

  2️⃣ Increasing atomic size

  3️⃣ Increasing boiling points

  4️⃣ Decreasing electronegativity
• The reactivity of halogens decreases down the group.
• Electronegativity decreases down the group for halogens.


  True
• Match the oxidation state of chlorine with the corresponding compound:

  -1 ↔️ NaCl

  +1 ↔️ HClO

  +3 ↔️ HClO₂

  +7 ↔️ HClO₄
• Order the halogens by their physical state at room temperature:

  1️⃣ F₂ (gas)

  2️⃣ Cl₂ (gas)

  3️⃣ Br₂ (liquid)

  4️⃣ I₂ (solid)

  5️⃣ At₂ (solid)
• Fluorine is the most reactive halogen.

  True
• Which halogen is the least reactive?

  Astatine
• Which halogen is the most reactive?

  Fluorine
• Halogens form compounds with other elements due to their high electronegativity.
• What is an example of a covalent compound formed by halogens?

  Chlorine monoxide
• Order the halogens from most reactive to least reactive.

  1️⃣ Fluorine

  2️⃣ Chlorine

  3️⃣ Bromine

  4️⃣ Iodine

  5️⃣ Astatine
• What is the general reaction for halogen displacement reactions?

  $2X +$$2Y^ - \rightarrow 2X^ - +$$Y_{2}$
• When chlorine gas is bubbled through a solution of sodium iodide, iodine and sodium chloride are formed.
• Match the halogen with its physical state at room temperature:

  Fluorine ↔️ Gas

  Bromine ↔️ Liquid

  Iodine ↔️ Solid
• What happens to the electronegativity of halogens as you move down the group?

  Decreases
• Match the halogen with its physical state at room temperature:

  Fluorine (F₂) ↔️ Gas

  Bromine (Br₂) ↔️ Liquid

  Iodine (I₂) ↔️ Solid
• The most common oxidation state of halogens is -1
• Match the oxidation state of chlorine with an example compound:

  +1 ↔️ Hypochlorous acid (HClO)

  +3 ↔️ Chlorous acid (HClO₂)

  +5 ↔️ Chloric acid (HClO₃)

  +7 ↔️ Perchloric acid (HClO₄)
• The boiling points of halogens increase down the group due to increasing London dispersion forces
• Halogens exhibit various oxidation states, with -1 being the most common
• The halogens are highly reactive nonmetal elements in the periodic table.


  True
• The melting and boiling points of halogens increase as you move down
• Halogens form halides with an oxidation state of -1
• Hydrogen fluoride (HF) is an example of a covalent compound.
• The reactivity of halogens increases as you move down the group.

  False
• What is an example of an ionic compound formed by halogens?

  Sodium chloride
• Halogens are safe to handle due to their low reactivity.

  False
• A more reactive halogen can displace a less reactive halogen from its compounds.
• In halogen displacement, what does Y represent?

  Less reactive halogen
• Which halogen is a reddish-brown liquid at room temperature?

  Bromine
• The melting and boiling points of halogens increase as you move down the group.
• Arrange the halogens in order of decreasing reactivity.

  1️⃣ Fluorine

  2️⃣ Chlorine

  3️⃣ Bromine

  4️⃣ Iodine

  5️⃣ Astatine