C4 - Predicting And Identifying Reactions And Products Flashcards
What are the group 1 metals?
Lithium, sodium, potassium, rubidium, caesium, francium
They all have one outer electron - thus have similar chemical properties
What are the common physical properties group 1 metals have?
Relative to other metals:
- Low melting points
- Low density
- Very soft
What type of compounds do alkali metals form?
Ionic compounds
How can you test for the presence of group 1 metal ions?
Using a flame test
Why are alkali metals reactive?
The outer electron is more easily lost because it is further from the nucleus, so the nuclear force of attraction is weaker and less energy is required to remove it
What are the Halogens?
Group 7 elements are known as the halogens
It is made up of Fluorine, Chlorine, Bromine, Iodine and Astatine
They all have 7 electrons in their outer shell
They also exist as diatomic molecules e.g. Cl2
Describe the trends going down the group 7 elements
As you go down group 7, the melting points and boiling points of the halogens increase.
Why does reactivity decrease going down group 7?
A halogen atom only needs to gain one electron in order to achieve a stable electronic structure.
As you go down the group, the halogens become less reactive as it gets harder to attract the extra electron due to the weaker nuclear force and the increased electron shielding
How are metal halides formed?
The halogens will react vigorously with alkali metals to form salts called metal halides
e.g. 2Na + Cl2 —> 2NaCl
Desribe a halogen displacement reaction?
A displacement reaction is where a more reactive element ‘pushes out’ (displaces) a less reactive element from a compound.
For example, chlorine is more reactive than bromine. If you add chlorine water to potassium bromide solution, the chlorine will displace the bromine from the salt solution.
e.g. Cl2 + 2KBr –> Br2 + 2KCl
Describe chlorine at room temperature:
Fairly reactive, poisonous, green gas
Describe bromine at room temperature:
Poisonous, red-brown liquid, which gives off an orange vapour
Describe iodine at room temperature:
Dark great crystalline solid which gives off a purple vapour when heated
What are the group 0 elements?
Group 0 elements are called the noble gases.
They include: helium, neon, argon, krypton, xenon, radon
They are all colourless gases at room temp
They have a full outer shell thus are more or less inert (unreactive)
Describe the properties of the transition metals
They have all the typical properties of metals - they are hard, strong and shiny materials that conduct heat and electricity
They have high melting points apart from Mercury
They also have high densities
They make very good catalysts e.g. iron is used in the Haber Process
The compounds of transition elements are also very colourful.
Most of the time, transition metals are much less reactive than Group 1 and 2 metals
