What are the structure of halogens?
Small molecules made up of pairs of atoms
Describe the pattern of the boiling and melting points going down the halogen group
Starts low and increases as you go down
What colour and state is fluorine at room temp?
Pale yellow gas
What colour and state is chlorine at room temp?
Green gas
What colour and state is bromine at room temp?
Red-brown liquid
What colour and state is iodine at room temp?
Grey solid
What does iodine easily evaporate to form?
A violet gas
Why do the halogens have low melting and boiling points?
They have small molecules made of pairs of atoms
What charge do halide ions always have?
-1
How can halogens bond with other elements?
- ionically with metals
* covalently with non metals
What are formed when halogens bond covalently?
Molecules
Describe the pattern of reactivity as you go down the halogen group
It decreases going down the group
What can a more reactive halogen do to a less reactive halogen from an aqueous solution of a halide compound?
The more reactive halogen can displace the less reactive halogen
How could you show that chlorine is more reactive than bromine?
Add choline solution to a solution of a metal bromide and bromine will be displaced by chlorine
Why does the reactivity decrease as you go down the halogens?
The attraction between the outer electrons and the nucleus decreases as the number of occupied shells increases
What type of element are the halogens?
Non metals
What is shielding?
When the number of shells increases making it harder for another electron to be attracted because it is less reactive
Why does the reactivity of a halogen depend on the attraction between the nucleus and the electrons?
The protons in the nucleus attract the electrons so if other electrons are shielding the nucleus then it is less reactive
Why does the density of a halogen increase going down the group?
Because of the high increase in mass and the small increase in volume as you go down the table
