P1.1.1 - The Model Of The Atom 1 Flashcards
What does the word ‘atomos’ mean in Greek?
Indivisible
What did Democritus and Leucippus think about atoms?
There would be a point when you could not cut anything anymore and you would have an atom
What was the Dalton model?
A strong, indestructible, hard sphere
What did dalton theorise about atoms?
All the atoms in an element are the same
The atoms in one element are different to all the atoms in all other elements
When was this model of the atom made?
During the 1870s
What did Dalton measure while experimenting?
How elements combined
What are cathode rays?
Rays given off by hot metals
What did Thompson discover?
Cathode rays were made of particles that were less that one thousandth the mass of a hydrogen atom
He discovered the electron which he thought must have come from inside the atom
He worked out that electrons have negative charges
When did Thompson’s investigations take place?
1897
What did Thompson have to make sense of?
An atom contains negatively charged electrons
Overall, an atom has an overall neutral charge
When was Thompson’s model introduced and what was it called?
It was called the plum pudding model and it came out in 1907.
What does the Plum Pudding model suggest?
Atoms consist of positive mass with negative electrons embedded in it
What did Thompson not know about the atom?
The structure of the atom and what the positive mass was made of
