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.
