s Flashcards
What is the atomic theory
The idea that everything is made up from little particles
that:
A) CANT be BROKEN DOWN ANY FURTHER
B) they are separated by empty space
Who proposed the atomic theory
Democritus
What did john dalton describe atoms as?
Solid spheres, that have different types which make up elements
What j.j thompson come up with?
the pudding model
Whats the pudding model
The scientific idea that an atom is a general ball of positive charge, with negatively charged electrons in it.
but it could not be
a) Couldnt be a solid sphere with no negative charge
How did Rutherford develop the nuclear model
in Rutherford’s experiments,particles were fired at a thin sheet of gold foil.
Most particles passed through, but some were
off course.
This caused him to hypothesise that there was a dense region of charge at the centre of the atom that repelled the alpha particles.
As a result he developed the nuclear model of the atom, in which there was a central positive nucleus, surround by
electrons.
What was the issue of rutherfords nuclear model?
One issue with Rutherford’s nuclear model was that the atom should collapse as the negative electrons would be attracted to the positive nucleus, causing them to rush inwards.
What did bohr suggest due to this
In response to this, in 1913 Bohr suggested that electrons orbit the nucleus in shells which prevents the atom from collapsing.
In the 20th century, Chadwick discovered neutral particles in the atomic nucleus. What are these particles called?
Neutrons
