C1:Atoms Bonding And Perodic Table Flashcards
Why were elements often placed in the wrong group in early versions of the periodic table?
Elements were placed in order of atomic weight rather than atomic mass, and didn’t take into account the elements chemical properties.
Summarise John Dalton’s theory
John Dalton described atoms as solid spheres, and said that different-sized spheres made up the different elements.
What is a halogen displacement reaction?
A reaction is which a more reactive halogen displaces a less reactive one.
What does the period tell you about the atoms of an element?
The period tells us the number of shells an atom has.
E.g. all elements in period 2 have 2 energy shells.
Give 3 special properties of transition metals (properties that normal metals don’t have).
*They make good catalysts. For example an iron catalyst us used in the Haber process to produce ammonia.
*Their ions are often coloured and so they can form colourful compounds.
*They can have more than one ion. For example copper can form Cu+ and Cu2+ ions.
Summarise the experiment carried out by Ernest Rutherford, and its results.
Experiment: Ernest Rutherford and his student conducted the alpha particle scattering experiments where they fired positively charged alpha particles at an extremely thin sheet of gold.
Results: Rather than all of the alpha particles passing straight through the sheet of gold as you would expect from the plum pudding model, some were deflected to the side, and a small number were even deflected backwards.
What does the ‘mass number’ of an atom tell you?
The total number of protons + neutrons the atom has.
Carbon-12 and carbon-13 are isotopes of carbon. How do they differ?
They have a different number of neutrons:
Carbon-12 has 6 neutrons.
Carbon-13 has 7 neutrons.
Describe the technique for crystallisation.
1.Pour the solution into an evaporating dish.
2.Heat it using a Bunsen burner.
3.Stop heating it when crystals start to form (‘point of crystallisation’) and allow it to cool down.
4.Either leave it to allow the rest of the water to evaporate, or filter out the crystals using filter paper and a funnel.
5.Dry the crystals in a warming oven or desiccator.
What is filtration used for?
Filtration is used to separate insoluble solids from liquids.
Noble gases are ‘inert’, what does ‘inert’ mean?
Inert mean they’re not reactive, so they don’t react with other atoms.
What is a solution?
A solution is a mixture that contains a solute (the solid) dissolved in a solvent (the liquid).
What is a element symbol?
An element symbol is a one or two letter abbreviation for a chemical element’s name.
For example:
Hydrogen is ‘H’
Carbon is ‘C’
Helium is ‘He’
Sodium is ‘Na’
Why did Mendeleev leave gaps in his table?
To ensure that elements with similar properties stayed in the same group, and to leave space for elements that hadn’t been discovered yet.
What is a mixture?
A mixture is a group of different elements or compounds which are not chemically bonded together.
