C3 Flashcards
What did Newlands do in 1864?
He made the Law of Octaves,as he noticed every eighth element had similar properties. Therefore they were listed in rows of seven. However this messed up on the third row-as transition metals messed it up.
Why was Newland’s work on the Law of Octaves criticised?
His groups contained elements that didn’t have similar properties.
He didn’t leave any gaps for undiscovered elements.
He mixed up metals and non metals.
What did Dmitri Mendeleev do?
He put the elements into a table and left gaps to predict future elements,and to make sure elements with similar properties were in the same group.
What is the modern Periodic Table based on?
Electronic Structure.
What is the trend for Group 1 Alkali Metals?
The further down the group you go,the more reactive the metals are,as the outer electron is more easily lost-as it’s further from the nucleus. Also,the lower the melting and boiling point are.
They also form ionic compounds with non metals to lose an outer electron.
What does an Alkali metal produce when reacted with water?
Hydrogen Gas.
What happens when Lithium,Sodium or Potassium are put in water?
They react vigorously.
They float and move about the surface,fizzing.
They produce Hydrogen-and the potassium gets hot enough to ignite it.
They form hydroxides that dissolve in water to give alkaline solutions.
What is the trend for Group 7:The Halogens?
They are less reactive the further down you go,as its harder to gain an extra electron because the outer shell is further from the nucleus. They have a higher melting and boiling point the further you go down the group.
What are the similar properties of the Halogens?
All non metals with coloured Vapours.
Form Ionic bonds with metals,to gain an electron.
More reactive halogens will displace less reactive ones.
What are the properties of Transition Metals?
Good conductors of heat and electricity.
Dense,strong and shiny.
Less reactive than group 1 metals.
Have higher melting points than group 1 metals.
Why are compounds colourful?
Due to the transition metal ion they contain.
What do Transition Metals make?
Good catalysts.
What does Hard Water make?
Scum and Scale.
How is Scum made?
When dissolved magnesium and calcium ions in the hard water react with the soap.
How is scale formed?
When hard water is heated.
What is Hard Water caused by?
Calcium and Magnesium ions.
What are the benefits of Hard Water?
Calcium ions are good for healthy teeth and bones.
Less risk of heart disease.
How is temporary hardness removed?
By boiling. The calcium hydrogen carbonate decomposes to form calcium carbonate which is insoluble.
How can Hard water be turned Soft?
By running water through an Ion Exchange Column. They have lots of sodium ions,which are exchange for the calcium or magnesium ions that run through them.
How can Water be made suitable for drinking?
It passes through a mesh screen to remove big bits like twigs.
Chemicals are added to make solids stick together,and fall to the bottom.
Water is filtered through gravel beds to remove all solids.
Water is chlorinated to kill off any harmful microbes left.
What are the disadvantages of adding Chlorine and Fluorine to water?
Linked with certain cancers.
People can’t choose not to have it.
What does Equilibrium mean?
The amount of reactants and products will reach a certain balance and stay there. The forward and backward reactions will cancel each other out.
How do you move the position of Equilibrium?
By changing the temperature:
Raise-endothermic reaction will increase.
Lower-Exothermic reaction will increase to give out more heat.
By changing the pressure:
Raise-encourage the reaction with less volume.
Lower-The reaction with more volume.
What is the Haber Process?
Nitrogen + Hydrogen – Ammonia
