Atomic structure Flashcards
Who made the Plum Pudding Model?
JJ Thomson
What did JJ Thomson discover?
Electrons
What experiment did Rutherford do?
Fired alpha particles at gold foil(can be squashed to one cell thick)
What model did Rutherford propose?
Nuclear model
What model did Niels Bohr propose?
Energy level model
In Bohr’s model of the atom where are the electrons?
In shells around the nucleus
Who discovered the neutrons?
James Chadwick
What does the mass number tell you?
Number of protons+Number of neutrons
The number of protons is the same as…
The number of electrons
What is the mass and charge of a proton?
Mass=1
Charge=+1
What is the mass and charge of a neutron?
Mass=1
Charge=0
What is the mass and charge of an electron?
Mass=Very small
Charge=-1
What does the nucleus of an atom contain?
Protons and neutrons
Which of these are neutral; atoms or ions?
Atoms
What does the atomic number tell us?(the bottom number)
How many protons there are
What does the mass number tell us?(the top number)
The total number of protons and neutrons in the atom
What is an element?
A substance that only contains atoms with the same number of protons.
What is an isotope?
Different forms of the same element, which have the SAME NUMBER OF PROTONS but a DIFFERENT NUMBER OF NEUTRONS.
What is the equation for relative atomic mass(Ar)?
Sum of (isotope abundance(%)x isotope mass number) / Sum of abundances(%) of all the isotopes
What is an example of compounds which are bonded ionically?
Sodium chloride
What is it called when positive and negative (opposite) charges of the ions are strongly attracted to each other?
Ionic bonding
What is covalent bonding?
When an atom shares an electron with another atom.
What is filtration used for?
If a product is an insoluble solid that needs to be separated from a liquid reaction mixture.
Explain the steps of evaporation
Pour the solution into an evaporating dish.
The solvent will evaporate, and the solution will get more concentrated. Eventually crystals will start to form.
Keep heating until all you have left are dry crystals.
Explain the steps of crystallisation
Pour the solution into an evaporating dish. Some of the solvent will evaporate and the solution will get more concentrated.
When crystal starts to form, remove the dish from the heat and leave the solution to cool.
After the salts becomes insoluble in the cold, filter the crystals out of the solution, and leave them in a warm place to dry.
What is simple distillation used for?
To separate out solutions
Explain the steps of simple distillation
The solution is heated. The part of the solution that has the lowest boiling point evaporates first.
The vapour is then cooled, condenses and is collected.
The rest of the solution is left behind in the flask.
What is fractional distillation used for?
Separate a mixture of liquids
Explain the steps of fractional distillation
Put the mixture in a flask and stick a fractional fractionating column on top, then heat it.
When the lowest boiling point matches, the temperature on the thermometer, it will reach the top of the column.
When the highest boiling point starts to evaporate, it will only get part of the way up before condensing since the column is cooler towards the top.
