Ions (TOPIC 5 + 6) Flashcards
How are Ions formed?
Ions form when atoms gain or lose electrons?
How do Ions become positively or negatively charged?
Ions that lose electrons are positively charged.
Ions that gain electrons are negatively charged.
What are the symbols and charges for the following Cations:
Ammonium
Hydrogen
Silver
Lead
Zinc
Ammonium - NH4+
Hydrogen - H+
Silver - Ag+
Lead - Pb 2+
Zinc - Zn 2+
What are the symbols and charges for the following anions:
Hydroxide
Nitrate
Carbonate
Sulfate
Hydroxide - OH -
Nitrate - NO3 -
Carbonate CO3 2-
Sulfate - SO4 2-
When ionic compounds are formed do metals and non-metals gain or lose electrons?
Metals lose atoms to become positively charged - cation
Non-metals gain atoms to become negatively charged - anion
What is ionic bonding?
A strong electrostatic force of attraction between oppositely charged ions.
Why do giant ionic lattices have high melting and boiling points?
As the strong electrostatic force of attraction between oppositely charged ions is very strong it takes a lot of energy to overcome.
Describe how to carry out a flame test.
Clean a platinum wire loop by dipping it in HCl an holding it in the flame.
Dissolve the unknown solid in water.
Soak the wire loop in the solution.
Place the wire loop in the blue part of the flame
Observe colour of the flame
What colour does lithium turn in the flame test?
Red
What colour does Sodium turn in the flame test?
Yellow
What colour does Potassium turn in the flame test?
Lilac
What colour does Calcium turn in the flame test?
Orange/red
What colour does Copper turn in the flame test?
Blue/green
What happens when you add a few drops of Sodium Hydroxide solution to Cu 2+
Blue precipitate
What happens when you add a few drops of Sodium Hydroxide solution to Fe 2+
Green precipitae
What do you do if you cannot identify the positive ion from the flame test?
Next mix 1.00 cm^3 of dilute sodium hydroxide to 1.00cm of the test substance.
Look for the precipitates.
Green - Fe 2+
Brown - Fe 3+
Blue - Cu 2+
What happens when you add a few drops of Sodium Hydroxide solution to Fe 3+
Brown precipitate
What if the the Sodium Hydroxide test does not work?
Is probably Ammonia. From the Sodium Hydroxide test you have just done warm it in a test tube and water bath.
Place damp red litmus paper at the mouth - if ammonia is present litmus paper turns blue.
What if the the Sodium Hydroxide test does not work?
Is probably Ammonia. From the Sodium Hydroxide test you have just done warm it in a test tube and water bath.
Place damp red litmus paper at the mouth - if ammonia is present litmus paper turns blue.
What if the the Sodium Hydroxide test does not work?
Is probably Ammonia. From the Sodium Hydroxide test you have just done warm it in a test tube and water bath.
Place damp red litmus paper at the mouth - if ammonia is present litmus paper turns blue.
What is the first step when testing for anions?
Add 1.00cm^3 of dilute nitric acid to 1.00cm3 of your test solution in a test tube. If there is effervescence it is probably Carbonate.
How do you test for carbonate?
Bubble the gas through limewater - the carbon dioxide will make it cloudy
If no effervescence occurs when nitric acid is added what is the next step?
The halide test.
To the nitric acid solution add 1 pipette of silver nitrate, observe the precipitates that form
White - Chlorine
Cream - Bromine
Yellow - Iodine
What colour precipitate does chlorine produce when mixed with nitric acid and silver nitrate?
White
What colour precipitate does Bromine produce when mixed with nitric acid and silver nitrate?
Cream
What colour precipitate does iodine produce when mixed with nitric acid and silver nitrate?
Yellow
What is the next step if no precipitate forms when silver nitrate is added to the solution?
With a new test tube add 1.00 cm^3 of the test solution and 1.00cm^3 of hydrochloric acid and another 1.00cm3 of barium chloride.
If white precipitate is produced a sulfate ion is present.
What colour is copper carbonate?
Green
