Group 17 Elements

Flashcards about Group 17 elements.

Halogens

Elements that constitute Group 17 (or Group 7) of the periodic table.

Fluorine

Pale yellow gas with the electronic configuration of 1s22s22p5.

Chlorine

Green gas and a halogen element.

Bromine

Brown/orange liquid at room temperature and pressure.

Iodine

Gray solid and a halogen element.

Boiling Point Trend (Halogens)

Increase down the group due to increasing van der Waals forces.

Electronegativity Trend (Halogens)

Decrease down the group due to increasing atomic size and shielding.

Hydrogen Halides

Acidic gases that dissolve in water to form acidic solutions.

Hydrochloric

Hydrogen chloride forms __ acid.

Hydrobromic

Hydrogen bromide forms __ acid.

Hydroiodic

Hydrogen iodide forms __ acid.

Thermal Stability of Hydrogen Halides

Decreases down Group 7 due to increased shielding and larger atomic size.

Silver nitrate and dilute nitric acid

What reagents are used to test for halide ions?

Result of Chloride ions reacting with silver nitrate

White precipitate is formed.

Result of Bromide ions reacting with silver nitrate

Cream precipitate is formed.

Result of Iodide ions reacting with silver nitrate

Yellow precipitate is formed.

Effect of ammonia on Silver chloride precipitate

Dissolves in dilute ammonia.

Effect of ammonia on Silver bromide precipitate

Dissolves in concentrated ammonia.

Effect of ammonia on Silver iodide precipitate

Insoluble in both dilute and concentrated ammonia.

Halogen Displacement Reaction

A reaction where more reactive halogen displaces a less reactive halide ion from a solution.

Function of Hexane in Halogen Displacement Reactions

It dissolves the halogen, forming a colored layer above the aqueous layer.

organic

The halogen dissolves in the __ solvent, forming a colored layer above the aqueous layer.

No Reaction

Chlorine + Potassium Chloride

Chlorine displaces bromine (Aqueous layer: Yellow, Organic layer: Orange)

Chlorine + Potassium Bromide

Chlorine displaces iodine (Aqueous layer: Brown, Organic layer: Purple)

Chlorine + Potassium Iodide

No Displacement

Bromine + Potassium Chloride

Bromine displaces iodine (Brown solution due to iodine formation)

Bromine + Potassium Iodide

Fluorine

Which halogen only forms oxidation states of 0 or -1 and cannot form positive oxidation states?

Disproportionation Reaction

Simultaneous reduction and oxidation of the same element.

Reducing Agent

Loses electrons in the reaction.

Iodide ions

Are stronger reducing agents than fluoride ions because they lose electrons more easily.

Initial reaction with sulfuric acid

Formation of sodium hydrogen sulfate and Formation of corresponding hydrogen halide.

Products with Bromide reaction with Sulfuric Acid

Sodium hydrogen sulfate, HBr, Br2, SO2

Sodium hydrogen sulfate, HI, I2, S, H2S

Iodide

The most powerful reducing agents among the halides and can reduce sulfuric acid to SO2, S, and H2S.

Iodide ions

Product of a disproportionation reaction

Sodium chlorate solution (bleach)

+1

NaClO, chlorine has an oxidation state of __.

Chlorine

Halogen that is used in swimming pools to kill bacteria.

Polyvinyl Chloride (PVC)

A polymer containing chlorine that is commonly used in homes.

What trend is observed in the boiling points of halogens as you descend Group 17, and why?

Boiling point increases due to increasing van der Waals forces with larger molecular size.

Describe the trend in electronegativity among the halogens as you move down Group 17. Explain the underlying reason.

Electronegativity decreases; this is because atomic size increases and there is greater shielding, reducing the effective nuclear charge.

When testing for halide ions using silver nitrate and dilute nitric acid, what would you observe if chloride ions are present?

A white precipitate of silver chloride (AgCl) forms.

Explain why iodide ions are considered stronger reducing agents compared to fluoride ions.

Iodide ions are larger and lose electrons more easily than fluoride ions due to weaker nuclear attraction on the outer electrons.