Atomic Structure and the Periodic Table Flashcards
Define a mixture.
two or more elements or compounds not
chemically combined together.
In what physical processes can a mixture be separated?
filtration,
crystallisation, simple distillation, fractional distillation and
chromatography.
What is chromatography used for?
Separation of coloured compounds.
What were atoms thought to be before the discovery of the electron?
Tiny spheres that could not be divided.
What model of the atom followed the discovery of the electron?
The Plum Pudding Model.
Describe The Plum Pudding Model.
The atom is a ball of
positive charge with negative electrons embedded within it.
What did Ernest Rutherford do to discover the nuclear model?
Fire alpha particles at a peace of gold leaf and observed scatter. Thusly proved that the mass of an atom was concentrated at the centre and that this was positively charged.
What was the Nuclear Model?
A model which suggested most of the mass of an atom was at a very small point (nucleus) which was positively charged orbited by electrons.
How did Niels Bohr adapt the nuclear model?
Suggested that electrons orbit at different distances.
How was the Nuclear model adapted to explain the nucleus?
The nucleus’ charge meant that it could be subdivided to a number of smaller positively charged particles. This was the introduction of the Proton.
How did James Chadwick contribute to the nuclear model?
Showed the existence of neutrons within the nucleus.
What are the relative electrical charges of particles in the atom?
Proton +1, Neutron 0, Electron -1.
In an element, the number of electrons is equal to?
The number of Protons.
What are the relative mases of particles in the atom?
Proton 1, Neutron 1, Electron ~0.
What is the atomic mass?
The sum of the protons and neutrons in an atom.
