Group 7 Flashcards
What is electronegativity?
It is the power of an atom in a molecule to attract electrons in a covalent bond to itself
Explain the trend in electron negativity down period seven
It decreases
Explain the trend and atomic radius down period seven
it increases due to the increasing number of shells and the nucleus is less able to attract bonding pair of electrons
Explain the trend in melting and boiling points down period seven.
It increases down the group as molecules become larger as they have more electrons or stronger and larger VDW forces as an intermolecular forces get larger more energy is required to break the forces which increases melting and boiling points
Fluorine is
A yellow pel gas
Chlorine is
A greenish reactive gas
Bromine is
Red brownish liquid
Iodine is
Black solid
Reactivity generally ……. Down the group.
Decreases
Explain displacement
A halogen reacting with a metal halide in the solution the halide will displace the reactive halogen for example, chlorine will displace bromine
What are the two tests for halide ions?
Reactions with sulphuric acid
Reaction with silver nitrate
What happens when chlorine reacts with sulphuric nitrate
It produces hydrogen sulphate
It is an acid base reaction
White misty fumes
What happens when chlorine reacts with sulphuric nitrate
It produces hydrogen sulphate
It is an acid base reaction
White misty fumes
What is the equation for when chlorine reacts with sulphuric acid? 
NACL + H2S04 ——> NAHS04+ HCL
What happens when bromine reacts with sulphuric acid?
It produces hydrogen sulphate and SO2
Why steamy fumes are formed and there is a brown vapour from the bromine
Give the equation for bromine reacting with sulphuric acid
It starts with acid base reaction and then a redux re
2Br- + H2 S04 + 2H+ —-> BR2 + SO2 + 2H2O
What is the reaction for when iodine reacts with sulphuric acid?
White steamy fumes of HI are formed
A black solid and purple fumes of iodine are formed
A colourless acidic gas of SO2
Yellow solid of sulphur
Hydrogen sulphide as a gas with a bad smell
What is the reaction with silver nitrate steps one
Add dilute nitric acid
This will remove any soluble carbonate and hydroxide which could react with the silver nitrate to form carbonates and hydroxide which are insoluble
What is the reaction with silver nitrate steps one
Add dilute nitric acid
This will remove any soluble carbonate and hydroxide which could react with the silver nitrate to form carbonates and hydroxide which are insoluble
What is the second step for reaction with silver nitrate and explain observations?
Add silver nitrate
Fluorine, no precipitate or form
Chlorine white precipitate forms silver chloride also forms
Bromine cream precipitate form and silver bromide
Iodine yellow precipitate form and silver iodide
Why does chlorine bromine and iodine react with silver nitrate?
Because it is insoluble
Step number three in reaction was silver nitrate and observation
Add dilute ammonia
Chlorine precipitate will dissolve and bromine and iodine doesn’t dissolve
What is the fourth step of halide reaction with silver nitrate and observation?
Add concentrated ammonia, bromine precipitate would dissolve an iodine doesn’t dissolve as insoluble
Explain the general steps of halide reaction with silver nitrate
Add dilute nitric acid which will remove any carbonate and hydroxide
Add silver nitrate form precipitate and eliminate fluorine
Add dilute ammonia which will dissolve the precipitate of chlorine
Add concentrate, ammonia, which will dissolve the precipitate of bromine leaving you with eye
What is disproportionation?
It is the name for the reaction where an element oxidises and reduces
