group 7 Flashcards
What type of molecules do halogens form? (1)
They form diatomic molecules.
How does the boiling point change down group 7? (1)
The boiling point increases as you go down the group.
Why does the boiling point increase down group 7? (3)
The number of electron shells increases, leading to more electrons.
This strengthens London forces, so more energy is needed to overcome intermolecular forces.
Therefore boiling point increases.
How do halogens react in redox reactions? (1)
They have 7 electrons in their outer shell
They react to gain one electron, forming 1⁻ ions.
How does reactivity change down group 7? (1)
Reactivity decreases as you go down the group.
Why does reactivity decrease down group 7? (2)
More electron shells and increased shielding decrease nuclear attraction.
More energy is needed to gain electrons, making it harder for halogens to react.
What happens when a more reactive halogen displaces a halide of a less reactive halogen? (1)
A color change occurs.
What is the result when chlorine (Cl₂) reacts with chloride ions (Cl⁻)? (1)
No reaction.
What is the result when chlorine (Cl₂) reacts with bromide ions (Br⁻)? (2)
Reaction occurs.
Gives an orange solution.
What is the result when chlorine (Cl₂) reacts with iodide ions (I⁻)? (2)
Reaction occurs.
Gives a brown solution.
What is the result when bromine (Br₂) reacts with chloride ions (Cl⁻)? (1)
No reaction.
What is the result when bromine (Br₂) reacts with bromide ions (Br⁻)? (1)
No reaction.
What is the result when bromine (Br₂) reacts with iodide ions (I⁻)? (1)
Reaction occurs.
Gives a brown solution.
What is the result when iodine (I₂) reacts with chloride ions (Cl⁻)? (1)
No reaction.
What is the result when iodine (I₂) reacts with bromide ions (Br⁻)? (1)
No reaction.
What is the result when iodine (I₂) reacts with iodide ions (I⁻)? (1)
No reaction.
How can bromine and iodine be distinguished in solution? (2)
Shake the solution with an organic solvent (e.g. cyclohexane).
A colour change will occur.
What is the colour of chlorine (Cl₂) in water? (1)
Pale green.
What is the colour of chlorine (Cl₂) in an organic solvent? (1)
Pale green.
What is the colour of bromine (Br₂) in water? (1)
Orange.
What is the colour of bromine (Br₂) in an organic solvent? (1)
Orange.
What is the colour of iodine (I₂) in water? (1)
Brown.
What is the colour of iodine (I₂) in an organic solvent? (1)
Violet.
What is disproportionation? (1)
The oxidation and reduction of the same element in a reaction.
