Atomic Structure and the Periodic Table Flashcards
What is the radius of an atom?
1x10^-10 m
What is the radius of the nucleus?
1x10^-14m
What is the formula for relative atomic mass?
(isotope abundance x isotope mass number) / sum of abundances of all the isotopes
What is chromatography used for?
To separate different dyes in an ink.
How do you do paper chromatography?
- draw a line near the bottom of a sheet of filter paper (in pencil as it is insoluble)
- Add a spot of ink and put the sheet in a beaker of solvent
- Make sure the ink isnt touching the solvent
- Place a lid to stop the solvent evaporating
- The solvent seeps up, and the dyes move at different rates so they separate.
When is filtration used?
When an insoluble solid is being separated from a mixture. It can also be used in purification.
How do you do the evaporation practical?
- Pour the solution into an evaporating dish
- Slowly heat the solution until dry crystals are left
When would you use crystallisation instead of evaporation?
If the produced salt breaks down when it is heated.
How do you do crystallisation?
- Pour the solution into an evaporating dish and gently heat it.
- Once crystals start to form, remove the heat and leave it to cool until crystals are fully formed
- Filter the crystals out of the solution and leave them to dry.
How can rock salt be separated?
- Grind the mixture so the salt crystals dissolve easily
- Put the mixture in water and stir.
- Filter the mixture.
- Evaporate the water from the salt.
What was the first theory for atoms?
John Dalton described atoms as solid spheres at the start of the 19th century.
Who discovered electrons and the plum pudding model and when?
JJ Thompson, in 1897
Who proved the plum pudding model wrong and when?
In 1909 Ernest Rutherford conducted his alpha particle scattering experiment.
What did Neil Bohr’s nuclear model show?
Electrons orbiting the nucleus in shells.
