Halogens Flashcards
What group elements are referred to as the halogens
Group 7
Name 2 properties of halogens
Low melting and boiling points
Exist as diatomic molecules
What is the trend in boiling point down group 7 and why
Increases down the group because:
Size of atom increases as more occupied electron shells
Stronger London dispersion forces between molecules
take more energy to break
What is the trend in reactivity down group 7 and why
Reactivity decreases because:
Atomic radius increases, electron shielding increases
Ability to gain an electron decreases
What is the trend in oxidising ability down group 7 and why
decreases because:
Number of occupied orbitals increases
weakest force of attraction between outer electrons and nucleus
More difficult to gain electrons
What is the colour of chlorine in water
Pale green
What is the colour of bromine in water
Orange
What is the colour of chlorine in cyclohexane
Pale green
What is the colour of bromine in cyclohexane
Orange
What is the colour of iodine in cyclohexane
Violet
Define disproportionation
Oxidation and reduction of the same element in a redox reaction
Why is chlorine added to drinking water
Kills microbes and makes it safer to drink
What are the two forms of chlorate ion
ClO - Chlorate (I)
ClO3 - Chlorate (V)
What is the equation for forming bleach
Cl2 + “NAOH –> NaCl + NaClO + H20
