The Halogens Flashcards
What type of molecule do they exist as?
Diatomic
True or false - they are toxic.
True
How does boiling point change down the group and why?
Increases Bigger molecule More electrons Greater electron shift Greater dipole Stronger VDW More energy required to overcome
Difference between halogens and halide.
Halogen has 7 e- on outer shell
Halide has 8 e- on outer shell hence is a 1- ion from gaining 1 e-
Trend in electronegativity down the group
Decreases Atomic radius increases Greater shielding Decreased attraction between positive nucleus and outmost electron Hence harder to gain an electron
Trend in oxidising ability down group
Decrease
Atomic radius increases
Increased shielding
Attraction between nucleus and outermost electron decreased
Hence ability to gain an electron is decreased
When will a halogen displace a halide?
If the halide is below it in the periodic table.
KCl + Cl2…
Does not occur
KBr+Cl2…
Yellow/brown solution formed
KI + Cl2…
Brown solution
Black ppt
KCl+Br2…
No reaction
KBr + Br2…
Does not occur
KI+Br2…
Dark brown solution
Black ppt
KCl + I2
Remains yellow
No change
KBr + I2…
Remains yellow
No change
KI + I2…
Does not occur
Cl- + Silver nitrate
White ppt
Br- + silver nitrate
Cream precipitate
I- + silver nitrate
Yellow precipitate
F- + silver nitrate
Dissolves, no ppt as AgF is very soluble
At- + silver nitrate
Brown precipitate
Trend in solubility down the group
Decreases
Cl- ppt in silver nitrate solution - name and formula
AgCl
Ag+ + Cl- -> AgCl
Br- ppt in silver nitrate solution - name and formula
AgBr
Ag+ + Br- -> AgBr
