2.2 - Group 7 Flashcards
(19 cards)
observations for halogen gases
Fluorine (F2): very pale yellow gas. It is highly reactive
Chlorine : (Cl2) greenish, reactive gas, poisonous in high concentrations
Bromine (Br2) : red liquid, that gives off dense brown/orange poisonous fumes
Iodine (I2) : shiny grey solid sublimes to purple gas.
trends in melting/boiling points down the group 7
Increase down the group
As the molecules become larger they have more electrons and so have larger London forces
between the molecules. As the intermolecular forces get larger, more energy has to be put into
overcoming the forces. This increases the melting and boiling points
Trends in electronegativity for group 7
Electronegativity is the relative tendency of an atom in a molecule to attract electrons in a covalent bond to itself. As one goes down the group the electronegativity of the elements decreases.
As one goes down the group the atomic radii increases due to the increasing number of shells. The nucleus is
therefore less able to attract the bonding pair of electrons
oxidising power of halogen
A halogen that is a strong oxidising agent will displace a halogen that has a lower oxidising power from one of its compounds
what happens to oxidising power down the group
The oxidising strength decreases down the group.
Oxidising agents are electron acceptors.
what is the reaction between potassium chloride and chlorine
no reaction
what is the reaction between bromine and potassium chloride
no reaction
reaction between iodine and potassium chloride
no reaction
reaction with potassium bromide and chlorine
cl displaces br
yellow solution
reaction between potassium bromide and bromine
no reaction
reaction between potassium bromide and iodine
no reaction
potassium iodide and chlorine
cl displaces I
brown solution
potassium iodide reaction with bromine
br displaces I
brown solution
potassium iodide reacts with iodine
no reaction
chlorine colour
very pale green solution
bromine colour
yellow solution
iodine colour
brown solution
what is a disproportion reaction?
Disproportionation is the name for a reaction where an element simultaneously oxidises and reduces.
reaction with chlorine and water
Cl2 (aq) + H2O(l) ⇌ HClO(aq) + HCl (aq)
