C2.4 - R* Group 7 - the halogens Flashcards
What are the group 7 elements called?
The group 7 elements are called the halogens
The group 7 elements
The group 7 elements are:
- Fluorine
- Chlorine
- Bromine
- Iodine
- Astatine
Halogens
The halogens are a group of toxic non-metals that have:
- Coloured vapours
- Fairly typical properties of non-metals
What are the fairly typical properties of non-metals?
The fairly typical properties of non-metals:
1. They have low melting points and boiling points
Their melting and boiling points increase going down the group
2. They are poor conductors of heat and electricity
As elements, what do the halogens all exist as?
As elements, the halogens all exist as diatomic molecules, made up of pairs of atoms
The electronic structure of the halogens determines the way they react with other elements.
How many electrons do they have in their outermost shell (highest energy level)?
The halogens have 7 electrons in their outermost shell (highest energy level)
What happens when halogens react with non-metals?
When halogens react with non-metals, they gain an extra electron by sharing a pair of electrons with another atom
How fluorine reacts with hydrogen
Fluorine reacts explosively with hydrogen
How chlorine reacts with hydrogen
Chlorine reacts explosively with hydrogen, in sunlight
How bromine reacts with hydrogen
Bromine reacts with hydrogen, only:
- At over 300 degrees Celsius
- In the presence of a platinum catalyst
How iodine reacts with hydrogen
Iodine reacts with hydrogen, only:
- At over 300 degrees Celsius
- In the presence of a platinum catalyst
Examples of halogens reacting with metals, when the halogen atoms gain a single electron to give them a stable arrangement of electrons and form ions with a 1- charge
Examples of halogens reacting with metals, when the halogen atoms gain a single electron to give them a stable arrangement of electrons and form ions with a 1- charge are:
- Sodium chloride
- Iron (III) bromide
To check the order of reactivity of the halogens, you can do what?
To check the order of reactivity of the halogens, you can carry out test tube reactions
What rule do you use when carrying out test tube reactions to check the order of reactivity of the halogens?
The rule you use when carrying out test tube reactions to check the order of reactivity of the halogens is that a more reactive halogen will displace a less reactive halogen from solutions of its salts
When carrying test tube reactions to check the order of reactivity of the halogens, you use what?
When carrying test tube reactions to check the order of reactivity of the halogens, you use solutions of:
- The halogens
- Their salts in water
When carrying out test tube reactions to check the order of reactivity of the halogens, what will the colour of the solution after mixing be due to?
When carrying out test tube reactions to check the order of reactivity of the halogens, the colour of the solution after mixing will be due to the less reactive of the pair of halogens