Group 7 Flashcards
Name the halogens, give their Color and physical state
• Fluorine= pale yellow= Gas
• Chlorine= Green= Gas
• Bromine= Red-brown= Liquid
• Iodine= Grey= Solid
Describe the trend in boiling points down Group 7
• Boiling points increase down the group
• Due to increase in strength of vander waals forces as size and relative mass of the of the molecule increases
Explain the trend in electronegativity down group 7
• Electronegativity decreases
• Larger atoms attract electrons less than smaller ones. This is because electrons are further from the nucleus and are shielded by more electrons
What happens when halogens react
They gain an electron
What is disproportionation?
A type of redox reaction in which there is mutual oxidation and reduction of the same element
What do halogens displace?
Less reactive halide ions from a solution
What type of halide does a halogen displace
A halide ion that is below it in the periodic table
What is the trend in oxidizing power as we go down group 7
Oxidizing power reduces
What happens when you mix chlorine gas with cold, dilute, aqueous sodium hydroxide
You get sodium chloride (I) solution. NaClO which is a common household bleach that kills bacteria
Give the uses of sodium chlorate (l) solution (bleach)
• Water treatment
• To bleach paper and textiles
• Clean toilets
Give the formula for chlorine and sodium hydroxide to make bleach
2NaOH(aq) + Cl2 (g) -> NaClO(aq) + NaCl(aq) + H2O(l)
What happens when you mix water with chlorine?
Chlorine undergoes disproportionation, you form chloride ions and chlorate(l) ions
What can chlorine do during sunlight
Chlorine can decompose to form chloride ions and oxygen
What are the benefits of treating water with chlorine?
•It kills disease causing micro organisms
•Some chlorine persists in the water and prevents reinfection further down the supply
•It prevents the growth of algae eliminating bad tastes and smells and removes discoloration caused by organic compounds
What are the risks of using chlorine to treat water?
• Chlorine gas is very harmful if breathed in because it irritates the respiratory system
• Liquid chlorine on the eyes or skin causes sever burns
• Chlorine reacts with organic compounds in water to form chlorinated hydrocarbons and many of these are carcinogenic (cancer-causing)
Describe the trend of reducing power down group 7
The reducing power of halides increases down the group
Explain the reason for the trend of reducing power down group 7
• Ions get bigger so the electrons are further away from the positive nucleus
• There are extra inner electron shells so there’s a greater shielding effect
• So further down the group the halide ion is, the easier it is to lose electrons and the greater the reducing power
What do all halides produce when they react with sulfuric acid
Hydrogen halide