C4 - Predicting And Identifying Reactions And Products

Lithium, sodium, potassium, rubidium, caesium, francium They all have one outer electron - thus have similar chemical properties

Relative to other metals: • Low melting points • Low density • Very soft

Ionic compounds

Using a flame test

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

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

As you go down group 7, the melting points and boiling points of the halogens increase.

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

The halogens will react vigorously with alkali metals to form salts called metal halides e.g. 2Na + Cl2 —> 2NaCl

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

Fairly reactive, poisonous, green gas

Poisonous, red-brown liquid, which gives off an orange vapour

Dark great crystalline solid which gives off a purple vapour when heated

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)

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

Potassium Sodium Calcium Magnesium Aluminium Zinc Iron Copper Silver

Metal + Water —> Metal Hydroxide + Hydrogen

You test for oxygen by placing a glowing splint near the mouth of the container of gas. If oxygen is present, the splint should relight.

You test for carbon duoxide using limewater, a calcium sulfate solution. If you bubble CO2 through a limewater solution, it should turn cloudy white.

You test for hydrogen by placing a lighted splint near the mouth of the container of gas. If hydrogen is present, it should ignite with a squeaky pop.

Use a drop of water to dampen a piece of blue litmus paper. Hold the paper near to the container that holds the substance If chlorine is present, the paper turns red then white.

• Add a few drops of dilute hydrochloric acid • Then a few drops of barium chloride solution If sulfate ions are present, you get a white precipitate

• Add a few drops of dilute hydrochloric acid If carbonate ions are present, bubbles of gas will be produced. Dilute nitric acid can also be used

• Add a few drops of dilute nitric acid • Then a few drops of silver nitrate solution If chloride ions are present - a white precipitate is formed If bromide ions are present - a cream precipitate is formed If iodide ions are present - a yellow precipitate is formed