Group 7- the halogens Flashcards
what do halogens exist as?
what does each molecule contain?
-simple molecules
-2 halogen atoms held by covalent bonds
what is the colour and state of chlorine?
pale green
gas
what is the colour and state of bromine?
brown
liquid
what is the colour and state of iodine?
purple-black
solid
what happens to the melting and boiling points of halogens as you go down the group?
they increase
why does the melting and boiling point of halogens increase as you go down the group? (3)
-the molecules become larger
-the intermolecular forces become stronger
-more energy is needed to overcome these forces
what does ‘halogen’ mean?
salt former
what do halogens react with metals to produce?
salts
what happens to the reactivity of halogens as you go down the group?
it decreases
what do halides react with hydrogen to produce?
hydrogen halides
what are hydrogen halides at room temperature?
gases
what do hydrogen halides dissolve in water to form?
acidic solutions
describe the Chemical test for chlorine:
-what about the other version?
Damp litmus paper is bleached white when it is placed in chlorine.
-If damp blue litmus paper is used, the paper turns red then white.
how do halogen displacement reactions work?
A more reactive halogen can displace a less reactive halogen from solutions of its salts.
why is it useless to test for the reaction of Cl and KCl?
A halogen cannot displace itself from a solution of one of its salts
