History Of The Atom Flashcards
What theory did John Dalton say about atoms and what time period was it?
At the start of the 19th century John Dalton describes atoms as solid spheres and said each sphere made up an element
What did JJ Thompson say about John Dalton’s theory andwhat time period was it in?
He concluded that John Dalton’s theory was not right because of his measurements of charge and mass showed that an atom must contain smaller negative charged particles
Called electrons in 1897
What scientist in 1897 discovered electrons
JJ Thompson
What was JJ Thompson‘s theory about atomic structure called?
The plum pudding model
Describe the plum pudding model and what it showed
Plum pudding model Was showed as a ball of Positive charge with electrons stuck to it and the mass was spread out
What was Ernest Rutherford Experiment and what did discover and what time period was it based in
He conducted a test or shooting positive alpha particles at a very thin gold sheet from the plum pudding theory they expected the particles to go straight through or some to be deflected because the plum pudding Theory stated the charge of the atom was very spread it out but what happened was someone straight through but some got deflected back this proves that the plum pudding model is not correct (1909)
Why did the coming back of particles in the earnest Rutherford experiment mean that the plum pudding model was not correct?
Because the plum pudding theory stated that all the atoms mass was spreading around But it must of taking something with a positive charge and the mass of the atom to be concentrated there to send that alpha particles backwards
What was Ernest Rutherford theory called
The nuclear model
What did the nuclear model State
There is a tiny positive charged nucleus at the centre where most of the mass is concentrated a cloud of negative electrons surround this Nucleus most of the atom is empty space
What did Neils Bohr state about electrons?
That all electrons were contained in shells rather than in a cloud
How did Neils Bohr describe electrons around the nucleus
He stated that electrons orbit the nucleus in fixed shells and each shell is a fixed distance from the Nucleus
How did Neils Bohr Theory support other scientists
It helped them explain their observations
Who discovered protons
Ernest RutherFord
Who discovered neutrons
James Chadwick
