history of the atom and periodic table Flashcards
what did dalton describe atoms as, early 1800
solid spheres, different spheres made up different elements
late 1800-what did jj thomson find
he found that they were not solid spheres
-found electrons
describe the plum pudding model– JJ
a ball of positive charge with electrons stuck in it
who proved the plum pudding wrong and how
rutherford, by conducting the alpha particle scattering experiment
what were the expectations of the alpha experiment
- alpha would pass through
- might be slightly deflected
what was the reality of the aloha experiment
- most went through
- some deflected more than expected
what did rutherford decide about the atom after the experiment
- he made the nuclear model
- nucleus in the centre
- most was empty space
name 2 differences between the plum pudding model and the nuclear model of the atom
PLUM PUDDING
-ball of positive charge
-electrons embedded into the ball
NUCLEAR MODEL
-positively charged nucleus at the centre
-most mass conc at the nucleus
-cloud of negative electrons surround the nucleus
who made the final model of the atom
Bohr
describe boars model of the atom
- electrons arranged in shells
- nucleus–p and n
- no overall charge, p and n cancel each other out
what was the periodic table arranged in earlier
-atomic mass, didn’t tae into account their properties
what did mendeleev do with the periodic table
left gaps and predicted elements
what did the old periodic table NOT include
nobal gases
