C1 - Atomic Structure Flashcards
What is an atom?
- the smallest part of an element that can exist
- what makes up all substances
What is a compound?
- formed from two or more elements by chemical reactions
What is a chemical reaction?
- involves the formation of one or more new substances
- sometimes a detectable energy change
What is a mixture? What about the chemical properties?
- two or more elements or compounds not chemically combined
- the chemical properties of each substance in the mixture are unchanged
Explain how to separate a mixture using filtration and what it is useful for
- Insoluble solid from liquid
- Passing mixture through filter paper using a funnel, leaving solid behind while liquid passes through
Give an example of filtration
Sand from a mixture of sand, salt and water
Explain how to separate a mixture using crystallisation
- Solution in evaporating basin, heated with bunsen burner
- Some water has evaporated, solid particles begin to form
- All water evaporated, leaving solid crystals behind
Give an example of crystallisation
Pure crystals of sodium chloride from salt water
Explain how to separate a mixture using fractional distillation
- Water and ethanol solution heated
- The ethanol evaporates first, cools, then condenses
- Collect pure ethanol
- The water left evaporates, cools, then condenses
- Column hot at the bottom and cool at the top, they rise and condense when below their boiling point
Give an example of fractional distillation
Separating different fractions from crude oil
Explain how to separate mixtures using simple distillation and what is it used for
- Salty water is heated
- The water vapour cools in the condenser and drips into a beaker
- The water has condensed and is now in the beaker, the salt stays behind
- To separate a solvent from a solution
Give an example of simple distillation
Separating pure water from sea water
Explain how to separate a mixture using chromatography
- Different substances travel different distances up the paper depending on their solubility in the solvent used
- The more soluble the more it moves
- Line in pencil as pencil won’t run
Give an example of chromatography
Separate out the dyes in food colouring
What was the Plum Pudding Model?
- Ball of positive charge with negative electrons embedded in it
- From discovery of the electron
What was the alpha scattering experiment?
- Concluded mass of an atom was concentrated at the centre and the nucleus was charged
- Positive particles thrown at a piece of gold foil
- Expected the particles to travel straight through
- Some bounced back and some deflected
- Suggested the positive charge and mass are in its centre - the nucleus
What was the nuclear model?
- Suggested electrons orbit the nucleus but not at set distances
What did Niels Bohr discover?
- Energy shells/levels
- Electrons at specific distances
What did James Chadwick discover?
- Carried out experiements for a particle with no charge
- Neutron discovery
What are isotopes?
- Atoms of the same element with different neutrons
What is the equation for relative atomic mass?
100
Describe the atomic structure of lithium
- 3 protons in the nucleus
- 4 neutrons in the nucleus
- 3 electrons which orbit the nucleus in electron shell
