8.2 The Halogens Flashcards
Halogens are diatomic, but in what form are they found naturally?
halide ions within stable compounds
What properties of halogens change down the group?
BOILING POINT ￪
ELECTRONEGATIVITY ￬
REACTIVITY / OXIDISING POWER ￬
Why does the boiling point of halogens increase down the group?
more electrons
stronger induced dipoles/London forces
more energy required to overcome intermolecular forces
Why does the electronegativity of halogens decrease down the group?
more shells
more shielding
weaker electrostatic attraction between shared pair + nucleus
(despite increased nuclear charge)
Why does the reactivity/oxisiding power of halogens decrease down the group?
halogens react/act as oxidising agents by gaining electrons:
- more shells
- greater shielding
- weaker electrostatic attraction of electrons to nucleus
- electrons gained less easily
Why are halogens a good oxidising agent?
ability to accept electrons
What colour is chlorine in water?
pale green
What colour is chlorine in cyclohexane?
pale green
What colour is bromine in water?
orange
What colour is bromine in cyclohexane?
orange
What colour is iodine in water?
brown
What colour is iodine in cyclohexane?
violet
What happens when cyclohexane is added to non-polar halogen molecules?
halogens dissolve more readily in cyclohexane than water
may be a colour change
What type of solvent is cyclohexane?
non-polar, organic
Why do halogens dissolve more readily in cyclohexane than in water?
cyclohexane is non-polar + so are halogens
so more/stronger intermolecular force interactions
