Atomic structure Flashcards
atomic number =
proton number = electron number
the bottom number on the periodic table
mass number=
total number of neutrons and protons
How can mixtures be separated? (5)
Filteration Cyrstllisation Simple distillation Fractional distillation Chromatography
What is Simple distillation?
obtains a solvent from a solution
What is Fractional distillation?
used to separate mixtures in which the components have different boiling points
In early models what were atoms though to be?
tiny spheres that could not be divided into simpler particles
Who discovered the electrons
what model was use ?
Describe the model
JJ Thomson
plum pudding
atoms contained tiny, negative electrons surrounded by a sea of positive charge
What was the alpha particle scattering and conducted it
Geiger and Marsden carried out an experiment
they bombarded a thin sheet of gold with alpha particles
What happened to the particles in the alpha partcle experiment
most of the positvely charged alpha particles passed straight through the atoms
a tiny number were deflected back towards the source
why did the new evidence from the scattering experiment led to a change in the atomic model
The results from the alpha particle scattering experiment led to the conclusion that the mass of an atom was concentrated at the centre (nucleus) and that the nucleus was charged.
If the plum pudding model was correct, the particles should have went straight through or be slightly deflected at the most. Instead more particles were deflected than normal
What model was created as a result of the alpha scattering experiment?
the nuclear model
What did Bohr discover?
electrons orbit the nucleus at specific distances, otherwise they would spiral inwards. The theoretical calculations of Bohr agreed with experimental observations.
Later experiments led to the idea that the positive charge of any nucleus could be _________
subdivided into a whole number of smallerparticles, each particle having the same amount of positive charge.
( this is a proton)
Who provided evidence of neutrons?
When?
James Chadwick
20 years after the nuclear model
What is the relative mass of an electron
very small
