C2.2 Flashcards
What is an ion
An atom/s with a positive or negative charge as it’s gained or lost electrons
What kind of ions are metal ions
They lose electrons and become positive so they are cations, attracted to negative cathode
What is the charge of an element in group one or two
They are metals so lose electrons. Group one, loses 1 electron, group 2 loses two electrons
WHat is the charge of ions from group 6 and 7
They are non metals so gain electrons. The amount they gain is 8-group number. E.g. Oxygen group 6 gains 2 electrons as 8-6=2
Charge of the ions for these elements NH4 K Na Ca Mg Cu Fe Al
1+ 1+ 1+ 2+ 2+ 2+ 2+ 3+
Charges of these ions Chloride Bromide Iodide Hydroxide Nitrate Oxide Carbonate Sulphate
Cl- Br- I- OH- NO3(-) O(2-) CO3(2-) SO4(2-)
Properties of ionic compounds
Conduct electricity when they’re molten or aqueous
Have high melting and boiling points
Very strong
What conditions are needed to conduct e,ectrixuty
Must be charged particles and they must be free to move
Why do ionic compounds only conduct when liquid
They have charged particles, the ions, but when solid they are locked into lactic structure so they can’t move. When they are molten or dissolved into an aqueous solution, the particles are free to move so they can conduct electricity
Soluble salts
All sodium, potassium and ammonium salts
All nitrates
Most chlorides
Most sulphates
Sodium, potassium and ammonium carbonates
Sodium, potassium and ammonium hydroxides
Which salts are insoluble
Silver chloride, lead chloride
Lead sulphate, barium sulfate, calcium sulfate
Most carbonates
Most hydroxides
What happens in a ppt reaction
Two aqueous solutions react to form an insoluble ppt in an aqueous solution
Why is barium sulphate used by hospitals
It is given to the patient as a barium meal. It is opaque in X-rays so shows up well. It is used to diagnose digestive problems as it builds up in places of abnormality so they can easily be located. Barium salts are toxic but barium sulphate can’t be dissolved so it’s safe to ingest as it can’t get into the blood
What colour do these ions burn Sodium Potassium Copper Calcium
Yellow
Lilac
Blue/green
Red
How can you test for chloride ions
Add few drops of nitric acid and mix, then add a few drops of silver nitrate, if chloride ions are present, a white ppt will form
