Inorganic- Group 7 / Halides Flashcards
What do you use to test for halide ions?
Acidified AgNO3
What is the trend in electronegativity as you go down group 7?
The electronegativity of the elements decreases
What is the trend in mp/bp as you go down group 7?
Increases down the group
Why does the mp/bp increase as you go down group 7?
The molecules become larger so they have more electrons and therefore have larger Van der Waals forces between the molecules so as intermolecular forces get larger more energy has to be put in to break the forces.
What are the physical states of the halogens?
Fluorine - yellow gas
Chlorine - green gas
Bromine - brown solution
Iodine - grey solid
What is the trend in reducing ability of the halides down the group?
Increases down the group because there are more occupied electron shells so outer electrons are further from the nucleus
- easier to be oxidised and loose electrons as you go down group 7, best reducing agent
What is the trend in oxidising ability down the group?
Decreases down the group, CI has fewest occupied electron shells, greatest force of attraction between outer electrons and nucleus, easiest to gain electrons and be reduced
-it is the best oxidising agent
What is the rule for displacement reactions of halide ions by halogens?
A halogen that is a strong oxidising agent will displace a halogen that has a lower oxidising power from one of its compounds
Explanation for oxidising power of the halogens
-Halogen atom gains an electron when it oxidises the halide ion
-the smaller the halogen atom, the easier it is to gain an electron as it is smaller and has less shielding
What reaction shows the reducing ability of halide ions?
Solid halides and concentrated sulphuric acid
What are the two stages that take place during a reaction with solid halides and concentrated sulphuric acid?
1) Displacement
2) Redox
What is the observation for sodium chlorides reaction with sulphuric acid?
White fumes
What is the symbol equation for chloride ions reaction with concentrated sulphuric acid?
NaCl(2) + H(2)SO(4) —>NaHSO(4) + HCl
What is the observation for sodium bromides reaction with sulphuric acid?
White/orange fumes
What is the symbol equation for bromide ions with concentrated sulphuric acid? 1st Reaction
NaBr + H(2)SO(4) —> NaSO(4) + HBr
