Chemistry of the elements Flashcards
What are periods
A period goes horizontally on the periodic table
Elements in the same period shared the same number of shells
Where are metals and nonmetals in the periodic table
Metals on the left hand side of the table and nonmetals are on the right hand side. There are more metals the non-metal
Explain the classification of elements as metals or nonmetals on the basis of their electrical conductivity and the acid-base character of their oxides
Metals are conductors whilst nonmetals are insulators and do not conduct electricity
Metals form basic oxides while nonmetals form acidic oxides
Why do elements in the same group of the periodic table have similar chemical properties
Each element in a particular group has the same number of electrons in the outer shell and this equals the group number. Elements in the same group have similar chemical reactions because they have identical numbers of electrons in their outer shells.
Why are noble gases unreactive
Noble gases (group 8) are very unreactive because there is no tendency to gain or lose an outer electron. However their density and boiling point increases down the group
What are the metals in group one called
The alkali metals
What are the similarities between all the group 1 elements
They have low density and are easy to cut, revealing a shiny silvery surface.
The alkali metals all have one electron in the outer shell and therefore all have similar reactions.
As you move down the elements in group 1 what is the change in the hardness density and melting point
The hardness decreases as you go down
the density increases as you go down
the melting point decreases as you go down
What do alkali metals give when they react with cold water
A metal hydroxide and hydrogen.
For example to Na + 2H2O goes to 2NaOH plus H2
Recall the relative reactivities of the elements in group 1
The vigour of the reaction increases with increasing atomic number. (Caesium reacts explosively with cold water).
What are all group 7 elements and what are they called
They are all non-metals and accord halogens.
What is the colour of chlorine bromine and iodine at room temperature and what state are they in
Chlorine is pale green and a gas
Bromine is red/brown and a liquid
Iodine is dark grey and a solid
What are the trends of the halogens with increasing atomic number
The melting point increases and the boiling point increases
What colour and what state is fluorine
at room temperature
It is a pale yellow gas with a low boiling point
Recall the relative reactivities of the elements in group 7
The bigger of the reactions decreases with increasing atomic number (this is opposite to the trend in group 1 the alkali metals get more reactive of the atomic number increases). The reactivity of the halogens decreases as the group is the sunders because electrons are attracted last readily to the halogen atom when the outer shell is further from the nucleus.
Describe experiments to show that a more reactive halogen will displace a less reactive halogen from a solution of one of its salts
Chlorine can displace bromine from sodium bromide solution.
Chlorine can displace iodine from sodium iodide solution.
Bromine can displace iodine from sodium iodide solution.
It follows that flooring can displace all of the halogens and can be displaced by no other. Astatine can displace no other halogens and can be displaced by all of the others.
Understand that all these reactions are redox reactions because one element is being oxidised while the other is being reduced
In the reaction between aqueous chlorine and sodium bromide solution what is being oxidised and what is being reduced
The chlorine is being reduced as it gains two electrons while the bromine is being oxidised as it loses two electrons
What is the percentage of the different gases in the air
Nitrogen – 78.1
Oxygen – 21.0
Argon– 0.9
Carbon dioxide – 0.04
Describe the experiment using copper in a tube connected to 2 gas syringes and using a Bunsen burner to work out the percentage of oxygen in air
You have copper in a silica tube connected on either end to a gas syringe one of the gas syringes starts with 100 cm³ of air. The gas is passed through the tube containing the copper which is being heated by pants and banner to the other gas syringe this is repeated several times. You continue this process until the end volume of our is no longer decreasing which shows that all the oxygen has reacted with a copper. From the amount of air you are left with you can tell how much oxygen there is as this will be the amount that has been lost.
Describe how you could measure the volume of oxygen in air using damp iron wool
A beaker with an upsidedown test tube with damp Iron wool at the top and filled with water the amount of water in the test tube is marked with a rubber band to show the initial volume of air. As the damp iron wool reacts with the oxygen the water level will rise in the tube. By then marking where the water has risen to you can tell how much oxygen was in the air.
How can you prepare oxygen from hydrogen peroxide
Hydrogen peroxide solution and solid manganese oxide Are put through a thistle funnel into a side-arm boiling tube. The manganese oxide acts as a catalyst for this reaction. The hydrogen peroxide breaks into water and oxygen. The oxygen rises and goes through the side arm of the boiling tube and is collected in an upsidedown test tube under water in a large beaker
What is a group
A group goes vertically on the periodic table
Elements with similar properties are in the same groups for example group 1 alkali metals and group 7 halogens.
Describe the reactions with oxygen in the air with magnesium, carbon and sulphur (equation flame colour and product)
Element magnesium, equation 2Mg + O(2) goes to 2MgO description, white flame, the oxide is a white solid
Element carbon, equation C + O(2) goes to CO(2) description, orange flame, the oxide is a colourless gas
Element Sulfur, equation S + O(2) goes to SO(2) description, blue flame, the oxide is a colourless gas
Write the equation the oxide and the character of the oxide for the reactions between magnesium oxide, carbon dioxide, and sulfur dioxide with water
Magnesium: MgO + H2O»_space;Mg(OH)2, magnesium hydroxide. It is basic.
Carbon: CO2 + H2O»_space;H(2)CO(3), carbonic acid. It is acidic.
Sulfur:SO2 + H2O»_space;H(2)SO(3), sulfuric acid. It is acidic.
How do you prepare carbon dioxide from calcium carbonate and dilutes hydrochloric acid
You have a side arm boiling tube with marble chips at the bottom and you put dilute hydrochloric acid through a thistle funnel. The carbon dioxide is formed through this reaction and is collected in an upsidedown test tube placed in a beaker full of water
Describe the formation of carbon dioxide from the thermal decomposition of metal carbonates such as copper(II) carbonate.
Copper carbonate is to copper oxide and carbon dioxide it
CuCO3»_space; CuO + CO2.
The copper carbonate turns from green to black copper oxide
Describe the reaction of dilutes hydrochloric acid and dilute sulphuric acid with magnesium
Magnesium reacts vigourously with Cold dilute acids and the mixture gets very hot. A colourless solution of magnesium chloride or sulphate is formed.
Mg(solid) + 2HCl(aqueous)» MgCl(2)(aqueous)+ H(2)
Mg(solid) + h(2)SO(4)(aqueous)» MgSO(4)(aqueous)+ H(2)(gas)
Describe the reactions of dilute hydrochloric acid and dilute sulphuric acid with aluminium.
Aluminium is slow to start reacting but after warming it reacts vigourously. This is due to the protective aluminium oxide layer on the surface of the metal.
2Al(solid) + 6HCl(aqueous)» 2AlCl(3)(aqueous)+ H(2)(gas)
2Al(solid) + 3H(2)SO(4)(aqueous)» Al(2)(SO4)(3)(aqueous)+ 3H(2)(gas)
Describe the reaction of dilutes hydrochloric acid and dilute sulphuric acid with zinc
Reacts slowly (more rapidly on heating). Zinc chloride or zinc sulphate is formed
Zn(solid) + 2HCl(aqueous)» ZnCl(2)(aqueous)+ H(2)(gas)
Zn(solid) + H(2)SO(4)(aqueous)» ZnSO(4)(aqueous)+ H(2)(gas)
Describe the reaction of dilute hydrochloric acid and dilute sulfuric acid with iron
Reacts slowly (more rapidly on heating). Iron (II) chloride or iron (II) sulphate is formed.
Fe(solid) + 2HCl(aqueous)» FeCl(2)(aqueous)+ H(2)(gas)
Fe(solid) + H(2)SO(4)(aqueous)» FeSO(4)(aqueous)+ H(2)(gas)
Describe the combustion of hydrogen
Hydrogen reacts with oxygen in the presence of a flame or spark to give water. A lighted splint placed at the mouth of a test tube of hydrogen will get a squeaky pop as a hydrogen reacts with the oxygen in the air. Larger volumes will give a loud explosion.
2H(2)(gas) + O(2)(gas)»_space;2H(2)O(liquid)
Describe the use of anhydrous copper (II) sulphate in the chemical test for water
Any water present in a mixture will turn anhydrous copper sulphate from white to blue
CuSO(4)(solid)(white) + 5H(2)O(liquid)»_space; CuSO(4).5H(2)O(solid)(blue)
Describe a physical test to show whether water is pure
You can put water in a beaker and heat it up while looking at a thermometer, if the water boils at 100°C it is pure
OR
You can put water in the freezer at exactly 0°C if it freezes the water is pure
List the reactivity series
Potassium Sodium Lithium Calcium Magnesium Aluminium(often appears less reactive because of it's protective oxide layer (Carbon) Zinc Iron-rusts slowly in moist air (Hydrogen) copper Silver Gold-unreactive, does not tarnish
Describe how all the elements in the reactivity series react with cold water
All the ones that do react give hydrogen and form alkaline hydroxides
Potassium-explodes Sodium-fizzes Lithium-fizzes Calcium-bubbles Magnesium-very slow reaction Aluminium-does not react with cold water Zinc-does not react with cold water Iron--does not react with cold water copper-does not react with cold water Silver-does not react with cold water Gold--does not react with cold water
Write the typical equation for potassium and cold water
2K + 2H(2)O»_space;2KOH + H(2)
Write the reactions of the metals in the reactivity series when heated with steam
All the metals that do react when heated with steam to give hydrogen and form metal oxides
Magnesium-reacts Aluminium-reacts Zinc-reacts Iron-reacts Copper-does not Silver-does not Gold-does not
Write the equation for magnesium reacting when heated with steam
Mg + H(2)O»_space; MgO + H(2)
What is different about calcium hydroxide than sodium or potassium hydroxides
It is less soluble and forms a white cloudy suspension as it is formed
In what situation does iron rust in cold water
It happens slowly only in the presence of air
What is rust
Iron oxide
Describe the reaction of the metals in the reactivity series with dilutes acid
The metals that do react with dilute hydrochloric and sulphuric acid form hydrogen and the metal chloride or sulphate
Potassium-explodes Sodium-reacts Lithium-Reacts Calcium-reacts Magnesium-reacts Aluminium-reacts Zinc-reacts Iron-reacts Tin-reacts Lead-reacts Copper-does not Silver-does not Gold-does not
If a metal is higher in the reactivity series will it displace a metal which is lower than itself in the reactivity series from a salt
Yes
Four example, Iron will displace copper from copper sulphate solution, and zinc will displace lead from lead nitrate solution, as shown by the equations:
Fe(solid) + CuSO(4)(aqueous) + Cu (solid)
Zn(solid) + Pb(NO3)2(aqueous)+Pb(solid)
Often the displaced metal appears as crystals on the surface of the more reactive metal
Two metals from the reactivity series competing for the less reactive one’s oxide. Which will take it and why?
The more reactive metal takes the oxygen because it combines more strongly with it. These reactions are highly exothermic as in the case of the thermit reaction (used to weld railway lines) in which aluminium and iron oxide react to form aluminium oxide and iron:
2Al +Fe(2)O(3)»Al(2)O(3) + 2Fe
What is oxidation and what is reduction in terms of the substance gaining or losing oxygen
A substance has been oxidised if it gains oxygen
A substance has been reduced if it loses oxygen.
What is a redox reaction
A reaction in which both reduction and oxidation are occurring
What is a reducing agent, and oxidising agent
A reducing agent is a substance which reduces something else (i.e. causes something else to lose oxygen).
An oxidising agent is a substance which oxidises something else (i.e. cause of something else to gain oxygen).
When magnesium and copper oxide go to magnesium oxide and copper which substance is oxidised and which reduced and which is the oxidising agent and which the reducing agent
Magnesium is oxidised and it is therefore the reducing agent.
The copper is reduced and is therefore the oxidising agent
Under what conditions does Iron rust
The corrosion of iron is known as rusting. Rusting occurs when iron or steel (an alloy containing iron) react with oxygen and water. Salt speeds up the reaction but it’s not essential.
What barrier methods are there of preventing iron from rusting
Paint/oil/Greece/plastic can all be used to cover I am preventing oxygen or water getting into it. This is called the barrier method.
What is sacrificial protection of iron and how does it work in terms of the reactivity series.
Metals that are more reactive than iron can be used as “sacrificial metals” as they will react instead of the iron. An example of this is galvanising Iron. This means coat in the iron with a layer of sink. Another method is to attach large lumps of magnesium or zinc to pipes or boat keels to also react instead of the iron
Describe simple tests for the gases hydrogen, oxygen, carbon dioxide, ammonia, chlorine
Hydrogen: a lighted splint pops.
The hydrogen combined explosively with oxygen
Oxygen: oxygen will really liked a glowing splint.
Carbon dioxide: carbon dioxide will turn limewater milky
Ammonia: it turns damp red litmus paper blue
Chlorine: chlorine is a gas that is green and that turns universal indicator paper red then bleaches so it turns white.
