Group 7 Halogens Flashcards
What colour and stare does fluorine exist as
Yellow gas
What colour and state does chlorine exist as
A green gas
What colour and state does bromine exist as
Brownish-red liquid (brown gas also)
What colour and state is iodine
Grey solid(forms purple gas)
What colour and state is astatine
Black solid
Are the halogens oxidising or reducing agents and why
They are oxidising agents because they take electrons from something else so oxidise it and are themselves reduced
Why does reactivity decrease down group
-halogens want to attract an electron in order to react and down the group the number of electron shells increases meaning there is more shielding between the bonding pair and the nucleus so the electrostatic force of attraction is weaker. In addition the bonding pair is further from the nucleus and these two factors outweigh the fact that nuclear charge increases down the group
How does oxidising power change down the group and what reactions does this mean can happen
Oxidising power decreases down the group meaning displacement reactions can occur between the halogens
Do halogens dissolve in organic solvents and what colours are shown
Dissolve freely in organic solvents and solutions have very similar colour to the free halogen vapours
Do halogens dissolve in water
Less soluble in water than in organic solvents however chlorine and bromine are still similar in colour to their vapours while iodine does not dissolve well so faint colour is present
How does electronegativity change down the group
Decreases down the group meaning the ability to attract electrons and hence react decreases as atomic radius and shielding increase which outweighs increase in nuclear charge meaning electrons in outer shells are less strongly attracted to nucleus
How does thermal stability change down the group
Thermal stability decreases down group as requires less energy to break hydrogen-halide bond down group because bonds between weaker as the halogen atom gets bigger meaning bond length is longer so bonding pair of electrons is further from halogen nucleus and the force of electrostatic attraction is less meaning the bond requires less energy to overcome.
How does melting and boiling point change down group 7
Increases down the group as van der waals forces between the diatomic molecules increases down the group as relative atomic mass of molecules increases meaning more energy is required to overcome the forces holding molecules together
How do the halogens act as oxidising agents
As they accept electrons from the species being oxidised and are reduced themselves
How does oxidising power change down the group
Decreases down the group as their ability to attract electrons decreases due to increased shielding and larger atomic radius, outweighs increase in nuclear charge
