2.1.1 Atomic Structure + isotopes Flashcards
What did john dalton suggest in 1803 causing what concept to be born
That matter was composed of invisible particles
Causing the atom concept to be born
What did JJ Thompson discover and say in 1897
Discovered electron
Said that negative electrons were embedded in a large positive mass like a plum pudding
What did Ernest Rutherford say in 1911
That mass and all the atoms positive charge were in a tiny nucleus
What did the discovery of the electron in 1897 lead to
Plum pudding model
What did the plum pudding model suggest
The atom was a ball of positive charge (pudding) with negative electrons embedded in it (dried fruit )
What did Geiger, marsden and Rutherford divide in 1909
A scattering experiment
What did the scattering experiment involve
Using alpha particles fired at very thin gold foil
What was the experiments prediction
That all positive alpha particles would be deflected a few degrees by the positively charged ‘pudding’of the gold atoms
What was the experiments conclusion
Most particles sailed straight through the gold foil like it wasn’t there and some bounced straight back at 180*
What did the evidence suggest
The atoms mass is mostly at the centre (nucleus) with the rest of the atoms being largely empty space
What showed that the gold nuclei must be positively charge
As the positive alpha particles had been repelled
What model replaced the plum pudding
Nuclear model
What did the nuclear model show
Positive nucleus surrounded by empty space
What did Niels Bohr do in 1913
Adapted model by suggesting electrons orbit the nucleus at specific distances (shells)
What was good about Neil’s bohrs results
His theoretical calculations agreed with experimental observations
