Halogens Flashcards
Where can the halogens be found?
In group 7
General properties? (5)
- Very reactive
- Toxic because of how reactive they are
- Brittle and crumbly when solid
- Poisonous and smelly
- They also become darker in colour down the group
What colour is fluroine?
Pale yellow gas (at room temp)
What colour is bromine?
Red/brown liquid (at room temp)
What colour is chlorine?
Yellow/green gas (at room temp)
What colour is iodine?
Grey solid (at room temp)
What does volatile mean? Which 2 gases are volatile?
Volatile means that they become gases easily.
Bromine and iodine are not gasesous but have low boiling points. So they produce vapours at relatively low temperatures.
What colour vapour does bromine produce?
Red-brown vapour
All group 7 elements are diatomic, what does this mean?
Diatomic means that all the halogens exist as diatomic molecules (they exist as two atoms covalently bonded together)
What is a halide ion?
A halide ion is when a halogem gains an electron to form a -1 charge.
What are ions like in halogens?
The halogens have 7 electrons in their outer shell, so they only need to gain one ELECTRON. When halogens gain an electron, they are known as HALIDE IONS (-1 ion).
Reactions with metals?
A halogen can react with a metal to gain electrons. When this happens they form an ionic compound, which is held together by ionic bonding.
When a metal and halogen react, they form salts called METAL HALIDES
Why does reactivity decrease down the group?
As you go down the group, there are more shells. This means that the outer shell is further away from the nucleus. So the force of attraction between the outer electrons and the nucleus gets weaker. WHICH MAKES IT HARDER FOR THE ATOM TO GAIN AN ELECTRON.
Displacement reactions in halogens?
A more reactive halogen will displace (take the place of) a less reactive halogen from a compound in a solution.
