Chemistry of the elements Flashcards
What’s a period?
Rows in periodic table
As you go along properties of elements change
What are groups?
Columns in the periodic table,
Elements in the same group have similar chemical properties due to having the same amount of electrons in outer shell
As the atomic number increases so the reactivity
Explain metals on the periodic table?
Left side of table including the zig zag
Conduct electricity
What are metal oxides?
Basic
What does basic mean?
They will neutralise acids, when dissolved will from a PH more than 7
Explain non metals on the periodic table?
Right side of periodic table including zig zag
Poor conductors of electricity
Are acidic dissolve with a PH more than 7
What the group 0 elements?
The noble gases, also inert (don’t react)
Why are the noble gases inert?
Have full shell of outer electrons, so don’t need to react
What happens when a group 1 metal reacts with water?
Group 1 metal (s) + water = group 1 metal hydroxide + hydrogen
What happens as you go down the group 1 metals? (atomic number increases)
They become more reactive
What happens when Lithium reacts with water?
Fizzing
Moves around water
Water goes Alkaline
What happens when Sodium reacts with water?
Heavy fizzing
Moves quickly around surface
May ignite
Water goes Alkaline
What happens when Potassium reacts with water?
Lilac flame
Explodes
Water goes Alkaline
In group 1 why do atoms become more reactive?
They lose their outer electron easier, as they are further away from the nucleus so there’s less attraction to keep them
What happens as the atomic number increase in group 7? (going down the group)
Darker colour, higher boiling point
Why the higher up in group7 the more reactive the element is?
Because the shell with the missing electron is nearer to the nucleus, so the pull from the positive nucleus is greater
What are the elements in group 7 called?
The halogens
Properties of Chlorine?
Green, gas at room temp
Properties of bromine?
Red-brown, liquid at room temp
Properties of Iodine?
Dark grey, solid at room temp
What happens when Halogens combine with hydrogen?q
They form hydrogen halides eg. Hydrogen Chloride
What happens when HCL is dissolved into water?
The HCL molecules split up into into H+ ions and CL- ions, this is dissociation creating Hydrochloric acid
Why is Hydrochloric acid acidic?
Due to the H+ ions
What happens if HCL is dissolved into Methylbenzene?
It doesn’t dissociate, so there are no H+ ions, so it’s not acidic
What’s a displacement reaction?
When a more reactive pushes out a less reactive element from a compound
In displacement reactions when is an orange solution formed?
When potassium Bromide displaces Chlorine from Chlorine water
In displacement reactions, when is a brown solution formed?
When Potassium Iodine solution displaces Bromine or chlorine from Bromine or Chlorine water
What do Halogen displacement reactions involved?
Transfer of electrons
How does a does transfer of electrons work in a displacement reaction?
The element displacing the other Element gains electrons to become negatively charged, whilst the other element becomes neutral
What’s oxidation?
Loss of electrons
What’s reduction?
Gain of electrons
What’s an oxidising agent?
An element which accepts electrons
What’s a reducing agent?
An element which donates electrons and gets oxdisede
What’s a redox reaction?
Where Reduction and oxidation happen at the same time
What’s the formula if you react an acid and metal?
Acid + Metal = salt + hydrogen
How is the speed measured when a acid reacts with a metal?
The amount of bubbles given off
How’s the hydrogen produced confirmed when an acid reacts with a metal?
Squeaky pop test
What salts does hydrochloric acid produce?
Chloride salts
What salts does sulphuric acid produce?
Sulphate salts
Equation when a metal reacts with water?
Metal + water = Metal Hydroxide + hydrogen
Which metals react vigorously with water?
Very reactive ones
Which metals only react steam?
Less reactive ones
Which metals don’t react with water or steam?
Extremely unreactive ones
What does the reactivity series show?
How well a metal reacts
What’s the reactivity series?
Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Copper Silver Gold
What does a more reactive metal to do a less reactive metal?
Displaces it, eg. Iron oxide + aluminium = Aluminium oxide + iron
What can these displacement reactions allow you to know?
The reactivity series
What has to be present for Iron or Steel to corrode to make rust?
Oxygen and water
Equation for when iron, oxygen and water mix?
Iron + Oxygen + water = Hydrated Iron + oxide (rust)
What’s the barrier method of preventing rust?
Paint the iron, or oil the iron, both keep the oxygen and water from the iron
What’s the sacrificial method of preventing rust?
Is putting a coating of a more reactive metal (galvanising), over the iron so the water and oxygen instead react with this
What percent if Nitrogen is in the air?
78%
What percent of oxygen is in the air?
21%
What percent of Argon is in the air?
1%
What percent of CO2 is in the air?
0.04%
With Copper how do you prove the air is 20% oxygen?
Heat copper with air, and see how much the air in the syringe, should be by 20%
How can you use Iron to prove the air is 20% oxygen?
Iron reacts with air to from rust, so some oxygen will be used up in the reaction, use iron wool with acetic acid (to catalyse the reaction) and see how much oxygen is used up in the reaction
How do you make Oxygen in the lab?
Decomposition of hydrogen peroxide into water and oxygen, using the catalyst manganese to speed the reaction up
What’s collection over water?
When you bubble the gas into an upside down measuring cylinder filled with water
What can you a gas syringe for?
To collect gas
What happens when a element reacts with oxygen?
An oxide is produced
What happens when magnesium reacts with oxygen?
Bright white flame
White powder (magnesium oxide)
Alkaline when dissolved in water
What happens when carbon reacts with oxygen?
Orange/yellow flame
Produces carbon dioxide gas
Acidic when dissolved in water
What happens when sulphur reacts with oxygen?
Pale blue flame
Produces sulphur dioxide gas
Acidic when dissolved in water
When do you use upward delivery to collect a gas?
When it’s lighter than air
When do you use downward delivery to collect a gas?
When it’s heavier than air
Equation for when calcium carbonate (marble chips) reacts with dilute hydrochloric acid?
Hydrochloric acid + calcium carbonate = Calcium chloride + water + carbon Dioxide
What’s a different way of creating CO2?
Heating a metal carbonate
What’s thermal decomposition?
When a substance breaks down into simpler substances when heated
Equation for when copper carbonate undergoes thermal decomposition?
Copper carbonate= Copper oxide + Carbon Dioxide
How to test for Carbonates?
Add dilute hydrochloric acid, if carbonates are present CO2 will be produced, check for this with limewater method
How to test for Sulphates?
Add dilute HCL followed by Barium chloride solution, if sulphates are present, white precipitate formed. (HCL added to remove carbonate or sulphite ions)
What’s a halide?
A bromide, chloride or iodide ion
How to test for Halides?
Add dilute Nitric acid, and Silver Nitrate solution
Once done the Halide test what will Chloride ions show?
White precipitate for silver chloride
Once done the Halide test what will Bromide ions show?
Cream precipitate for silver Bromide
Once done the Halide test what will Iodide ions show?
Yellow precipitate for silver iodide
Why is the Nitric acid added in the halide test?
To get rid of Carbonate or Sulphite ions
Test for chlorine?
Bleaches damp litmus paper
Test for oxygen?
Relights a glowing splint
Test for Carbon Dioxide?
Turns limewater cloudy
Test for Hydrogen?
Squeaky pop with a lighted splint
Test for Ammonia?
Turns damp litmus paper blue
What can you use a test for water?
Copper sulphate crystals, blue when water is present, white when it isn’t (anhydrous)
What does it mean if a sample is pure?
Only one substance, so it has defined physical properties eg. melting and boiling point
What are the group 1 elements called?
The alkali metals
