C1- Atomic Structure Flashcards
What are all substances made up of?
1) All substances are made up of atoms.
Explain what an atom is. What do atoms contain?
1) An atom is the smallest part of an element that can possibly exist.
2) Atoms contain protons, neutrons and electrons.
What are the charges of protons, neutrons and electrons?
1) Proton: +1 charge
2) Neutron: 0 charge
3) Electron: -1 charge
What are the relative masses of protons, neutrons and electrons?
1) Proton: 1
2) Neutron: 1
3) Electron: very small.
Explain what a compound is.
How are they formed?
How can they be separated?
1) A compound contains two or more elements chemically combined in fixed proportion.
2) They are formed from elements by chemical reactions.
3) Compounds can only be separated into elementrs by chemical reactions.
Explain what a mixture is.
How can mixtures be separated?
1) A mixture consists of two or more elements or compounds not chemically combined together.
2) Mixtures can be separated by physical processes such as filtration, crystallisation, simple distillation, fractional distillation and chromatography.
Describe the method of separating substances using chromatography.
1) Draw a line near the bottom of a sheet of filter paper using pencil.
2) Add a spot of the ink to the line and place the sheet in a beakerof solvent (water)
3) The solvent used depends on what is being tested.
4) Ensure that the ink isn’t touching the solvent. You dont want it to dissolve.
5) Place a lid on top of the container to stop the solvent evaporating.
6) The solvent seeps up the paper, carrying the ink with it.
7) Each different dye will move up the paper at different rates. The dyes will separate out. Each dye will form a spot in a different place.
8) If any of the dyes in the ink are insoluble in the solvent used, they will stay on the baseline.
9) When the solvent has nearly reached the top of the paper, take paper out of the beaker and leave it to dry.
How do you use evaporation to separate soluble solids from solutions?
1) Evaporation:
- Pour solution into an evaporating dish. Slowly heat the solution. The solvent will evaporate and the solution will become more concentrated. Crystalls will start top form. Keep heating the evaporating dish and then you will be left with dry crystal.
How do you use Crystallisation be used to separate solubile solids from solutions?
1) Crystallisation:
- Pour the solution into an evaporating dish and gently heat it.
- Some of the solvent will evaporate which means that the solution will get more concentrated. Once you see some crystals start to form, remove the dish and let it cool.
- The salt should start to form crystals as it become insoluble in the concentrated solution.
- Filter the crystals out of the solution and leave in a warm place to dry. You could use a desicator
How do you use distillation to separate out solutions?
1) Heat the solution. The part of the solution that has the lowest boiling point will evvaporate first.
2) The vapour is then cooled, condenses and is collected.
3) The rest of the solution is left behind in the flask.
5) You can use simple distillation to get pure water from seawater. The water evaporates and is condensed and then collected.
What are some issues with simple distillation?
1) You can only use it to separate things with very different boiling points.
What did John Dalton describe atoms as>
1) He described atoms as solid spheres and said thst different spheres made up the different elements.
What did JJ Thompson discover? What did this suggest?
1) He made the plum pudding model.
2) The plum pudding suggested that the atom is a ball of positive charge with negative electrons embedded on it.
Who showed that the Plum pudding model was wrong? What did this person discover?
1) Ernest Rutherford showed that the Plum pudding model was wrong.
2) He conducted the alpha particle scattering experiments. It states that the mass of an atom was concentrated at the centre of an atom and that the nucleus was charged.
What did Niels Bohr suggest?
1) Niels Bohr suggested that electrons orbit the nucleus at specific distances.
