Elements of the Sea: Group 7 Flashcards
What are the solutions of chlorine bromine and iodine and why ( in terms of redox )
Oxidising agents because the elements gain electrons ( get reduced )
What are the solutions of chloride bromide and iodide and why ( in terms of redox )
Reducing agents because the ions lose electrons
Definition of halogen
Group 7 diatomic molecules
Examples of halogens
Chlorine, Cl2
Bromine, Br2
Fluorine, F2
Definition of halide ions
Group 7 ions
Examples of halide ions
Chloride, Cl-
Bromide, Br-
Fluoride, F-
Appearance of chlorine at room temp
Pale green gas
Appearance of bromine at room temp
Dark red liquid
Appearance of iodine at room temp
Shiny grey solid
Appearance of aqueous solution of chlorine at room temp ( chlorine in water )
Pale green
Appearance of aqueous solution of bromine at room temp ( bromine in water )
Orange/ yellow
Appearance of aqueous solution of iodine at room temp ( iodine in water )
Brown
Appearance of cyclohexane solution of chlorine at room temp
Pale green
Appearance of cyclohexane solution of bromine at room temp
Red/ brown/ orange
Appearance of cyclohexane solution of iodine at room temp
Violet
What happens to the solubility of silver halides when you add ammonia ( give examples )
Sobulitt decreases as you go down the group
Eg. AgCl = soluble
AgBr = partly soluble
AgI = insoluble
What happens when you mix Chlorine (aq) and bromide ion (aq)
-give equation & explanation
Yellow solution forms
Cl2 + 2Br- —> 2Cl- + Br2
= chlorine displaces bromide ion because chlorine has stronger oxidising power
What happens when you mix Chlorine (aq) and iodide ions (aq)
-give equation & explanation
Brown solution forms
Cl2 + 2I- —> 2Cl- + I2
= chlorine displaces iodide ion because chlorine has stronger oxidising power
What happens when you mix Bromine (aq) and iodide ions (aq)
-give equation & explanation
Brown solution forms
Br2 + 2I- —> 2Br- + I2
= bromine displaces iodide ion because bromine has stronger oxidising power
What happens when you mix a halogen that has a weaker oxidising power than the halide
Eg. Bromine & chloride ions
No reaction
Give the order of halogens in strongest to weakest of oxidising power
Chlorine
Bromine
Iodine
What is the trend of oxidising power of halogens ad you go down the group
Decreases as you go down the group
Explain why oxidising power decreases as you go down the group
- Halogen atom gains an electron when it oxides the halide ion
- atomic radius increases
- increase shells
- increase shielding
- decrease ability to attract electrons ( gets weaker )
Appearance of fluorine at room temp
Pale yellow gas
What happens to the melting and boiling point as you go down the group
Increase
Reason for trend in physical properties ( colour, mpt, bpt )as you go down the group
Strength of intermolecular forces increases as you go down the group
What happens to reactivity as you go down the group
Decreases
Why does group 7 reactivity decrease as you go down the group
- increase atomic radius
- increased shielding
- nuclear charge is further away from the outer shell to attract electrons
What happens to ionisation energy as you go down the group
Decreases
Why does ionisation energy decreases as you go down the group
- increase atomic radius
- increased shielding
- nuclear charge is further away from the outer shell
- less energy required to remove electrons
