A3 - Group 7 Flashcards
What is the state of fluorine?
Gas
What is the state of chlorine?
Gas
What is the state of bromine?
Liquid
What is the state of iodine?
Solid
What is the state of astatine?
Solid
What is the trend in electronegativity as you go down group 7?
As you go down group 7:
- Electronegativity decreases because…
- The number of protons increases
- The atomic radius increases
- Shielding increases
- These factors outweigh the increasing number of protons
- Meaning there is a weaker attraction between the nucleus and outer electron
- So there is less tendency to attract another electron to fill the outer shell
What happens when group 7 elements react?
They are reduced, but can also be called oxidising agents.
What is the colour of chlorine in an aqueous solution?
Pale green (almost colourless)
What is the colour of chlorine in an organic solution?
Pale green (almost colourless)
What is the colour of bromine in an aqueous solution?
Orange
What is the colour of bromine in an organic solution?
Orange
What is the colour of iodine in an aqueous solution?
Brown
What is the colour of iodine in an organic solution?
Violet
What is the oxidising power of chlorine, bromine and iodine in order of strongest oxidising agent to the weakest?
Strongest: Chlorine
Bromine
Weakest: Iodine
Explain the trend in reactivity as you go down group 7:
As you go down group 7 the electron affinity decreases because:
- Atomic radius increases
- Shielding increases
- Nuclear attraction decreases so it becomes harder to gain an electron
What is the observation of chloride ions with silver nitrate?
White ppt
What is the observation of bromide ions with silver nitrate?
Cream ppt
What is the observation of iodide ions with silver nitrate?
Yellow ppt
What is the observation of chloride ions with dilute ammonia?
Ppt disappears
What is the observation of bromide ions with dilute ammonia?
No change
What is the observation of iodide ions with dilute ammonia?
No change
What is the observation of chloride ions with concentrated ammonia?
Ppt disappears
What is the observation of bromide ions with concentrated ammonia?
Ppt disappears
What is the observation of iodide ions with concentrated ammonia?
No change
