Group 7

• What is the general name for the elements in Group 7 of the periodic table?

  Halogens
• The halogens are located on the right-hand side of the periodic table.
• What is the physical state of fluorine at room temperature?

  Gas
• Chlorine gas is pale green in color.
• Match each halogen with its electron configuration:

  Fluorine ↔️ 1s2 2s2 2p5

  Chlorine ↔️ 1s2 2s2 2p6 3s2 3p5

  Bromine ↔️ 1s2 ... 4s2 4p5

  Iodine ↔️ 1s2 ... 5s2 5p5
• Arrange the halogens in order of increasing boiling points.

  1️⃣ Fluorine

  2️⃣ Chlorine

  3️⃣ Bromine

  4️⃣ Iodine
• As we go down Group 7, the molecules become larger, resulting in larger Vander Waals forces.
• Bromine is a brown-orange liquid at room temperature.
• What happens to electronegativity as you move down Group 7?

  Decreases
• Electronegativity decreases because the distance between the nucleus and bonding electrons increases.
• Arrange the halogens in order of decreasing electronegativity.

  1️⃣ Fluorine

  2️⃣ Chlorine

  3️⃣ Bromine

  4️⃣ Iodine
• What is the fundamental rule for displacement reactions involving halogens?

  More reactive displaces less
• In a displacement reaction, a more reactive halogen displaces a less reactive halide ion.
• The reactivity of halogens increases as you move down Group 7.

  False
• What is the color of iodine when it is dissolved in solution?

  Brown
• When chlorine reacts with bromide ions, an orange solution indicates the formation of bromine.
• Which halogen reacts with potassium iodide to form iodine and potassium chloride?

  Chlorine
• Bromine is more reactive than chloride ions.
• What type of reaction is used to make bleach?

  Disproportionation
• Bleach is formed when chlorine reacts with sodium hydroxide.
• In the formation of bleach, chlorine is simultaneously oxidized and reduced.
• What is the oxidation state of chlorine in sodium chlorate(I) in bleach?

  +1
• Adding chlorine to water sterilizes it by killing bacteria.
• Sunlight can decompose chlorinated water, reducing its effectiveness.
• What compound is formed when chlorine reacts with water in the presence of sunlight?

  Oxygen
• What are the advantages of chlorinating drinking water?

  Destroys microorganisms
• One disadvantage of chlorinating drinking water is that chlorine can react with organic compounds to form chloro alkanes.
• Match each halide ion with its ability as a reducing agent:

  F- ↔️ Weakest

  Cl- ↔️ Stronger

  Br- ↔️ Even stronger

  I- ↔️ Strongest
• Iodide ions are better reducing agents than fluoride ions.
• What happens to the ionic radius of halide ions as you move down Group 7?

  Increases
• The attractive force between the nucleus and outer electrons becomes weaker due to increased shielding.
• Sulfuric acid can be reduced to form sulfur dioxide with the oxidation state of sulfur changing from +6 to
• Which halide ion does not react with concentrated sulfuric acid to produce sulfur dioxide?

  Chloride
• The reaction of chloride ions with concentrated sulfuric acid is a redox reaction.

  False
• The reaction of bromide ions with concentrated sulfuric acid produces orange vapor, indicating the formation of bromine
• What is the oxidation state of sulfur in H2S?

  -2
• Steps in balancing half equations for redox reactions

  1️⃣ Balance the atoms other than oxygen and hydrogen

  2️⃣ Balance oxygen by adding water

  3️⃣ Balance hydrogen by adding protons

  4️⃣ Balance the charge by adding electrons
• Half equations must be balanced to ensure the number of electrons is the same on both sides.
• What gas with a rotten egg smell is produced when iodides react with concentrated sulfuric acid?

  H2S
• Match the precipitate color with the corresponding halide ion:

  White ↔️ Chloride

  Cream ↔️ Bromide

  Yellow ↔️ Iodide