Chapter 9 Flashcards
What are the diatomic molecules of halogens?
Fluorine (F2), Chlorine (Cl2), Bromine (Br2), Iodine (I2)
All halogens exist as diatomic molecules.
Describe the physical state and color of Fluorine (F2).
Very pale yellow gas
Fluorine is highly reactive.
Describe the physical state and color of Chlorine (Cl2).
Greenish, reactive gas
Chlorine is poisonous in high concentrations.
Describe the physical state and color of Bromine (Br2).
Red liquid, gives off dense brown/orange poisonous fumes
Describe the physical state and color of Iodine (I2).
Shiny grey solid, sublimes to purple gas
What is the trend in melting and boiling points of halogens down the group?
Increase down the group
Larger molecules result in more electrons and larger induced dipole-dipole forces.
What is the electronic configuration of all group 7 elements?
s2p5
How do halogens typically react in redox reactions?
By gaining one electron to form 1– ions
What occurs in a displacement reaction involving halide ions?
A more reactive halogen displaces a less reactive halogen from its compound
How does reactivity of halogens change down the group?
Decreases down the group
Which halogens can chlorine displace?
Bromide and iodide ions
What color indicates the presence of Chlorine in an aqueous solution?
Very pale green solution (often colorless)
What color indicates the presence of Bromine in an aqueous solution?
Yellow solution
What color indicates the presence of Iodine in an aqueous solution?
Brown solution
What happens to the color of the solution when an organic solvent is added?
Chlorine = colorless, Bromine = yellow, Iodine = purple
Why is chlorine more reactive than bromine?
Chlorine is smaller and less shielded, attracting electrons more strongly
What is disproportionation?
A reaction where an element simultaneously oxidizes and reduces
What is the reaction of chlorine with water?
Cl2(g) + H2O(l) → HClO(aq) + HCl(aq)
What is the role of chlorine in water treatment?
Kills bacteria in drinking water and swimming pools
What is the reaction of chlorine with cold dilute NaOH?
Cl2(aq) + 2NaOH(aq) → NaCl(aq) + NaClO(aq) + H2O(l)
What is produced when chlorine reacts with hot sodium hydroxide?
Sodium chlorate(V)
What test identifies halide ions?
Reaction with silver nitrate solution
What precipitate do chlorides produce in the presence of silver nitrate?
White precipitate
What precipitate do bromides produce in the presence of silver nitrate?
Cream precipitate
