3.1.3 The Halogens Flashcards
What group are the halogens in
Group 7
What are the halogens
Non-metals that can consist of diatomic molecules
4 halogens to know and their halides
Fluorine, F2 - Flurodie, F-
Chlorine, Cl2 - Chloride, Cl-
Bromine, Br2 - Bromide, Br-
Iodine, I2 - Iodide, I-
What is fluorine, F2 in the form of at room temp
Pale yellow gas
What is Chlorine, Cl2 in the form of at room temp
Pale green gas
What is Bromine, Br2 in the form of at room temp
What colour vapour does it form
Dark red liquid and forms orange vapour
What is iodine, I2 in the form of at room temp
What vapour does it form
Grey solid
Forms purple vapour
Going down group 7, what happens to atomic radius
Gets larger as each element has 1 extra electron shell
What’s electronegativity
Measure of the ability of an atom to withdraw electron density in a covalent bond towards itself
What happens to electronegativity going down group 7
Why
Decreases
Due to increased shielding causing a weaker attraction by the nucleus
What happens to both melting and boiling point going down group 7
Why
Increases
As larger atoms have mor electrons making induced dipole-dipole forces between molecules stronger
What do oxidising agents like the halogens do
Accept electrons from another species
What’s the strongest oxidising agent of all the halogens
F2
What happens to the oxidising power going down a group
Why
It decreases
As the atomic radius increases + nuclear charge effect is reduced due to increased shielding
Larger halogens gain an electron less readily
What reactions are displacement reactions
Redox
How can a halogen displace another
If it’s a stronger oxidising agent
What solution does bromine produce in a displacement reaction
Orange solution
What solution does iodide produce in a displacement reaction
Violet/purple solution
What’s the weakest oxidising agent of the halogens
Iodide, I2
What halogen displaced both Br- and I-
Chlorine
What halide will Br2 only displace
I-
What 2 halogens both appear brown when forming solutions so it’s difficult to tell them apart
How can you distinguish between the two
Br2
I2
Distinguish by adding cyclohexane
When cyclohexane is added to either Br2/I2 and shaken, what does it produce (2)
Orange layer - If Br2(aq)
Purple/violet layer - if I2 (aq)
