Atomic Models

Question 1

what was Daltons model

Answer 1

atoms = solid spheres
different spheres = different elements

Question 2

what was Thomsons conclusions (1897)

Answer 2

• atom must contain smaller, negatively charged particles > plum pudding model

Question 3

describe the plum pudding model

Answer 3

a positive charged ball (“pudding”) with electrons throughout

Question 4

describe Rutherfords gold foil experiment

Answer 4

• fired alpha particles (positively charged) at gold foil

Question 5

what were Rutherfords expectations of the gold foil experiment

Answer 5

• expected most of the alpha particles to be slightly deflected because of the “positive pudding”

Question 6

what actually happened with the gold foil experiment

Answer 6

• most particles passed straight though
• very small number deflected backwards

Question 7

what conclusions did Rutherford experiment (gold foil) lead to

Answer 7

that the atom was mostly empty space

Question 8

describe Rutherfords nuclear model

Answer 8

• small positively charged nucleus at the centre
• cloud of negative electrons

Question 9

why was a new model of the atom suggested after Rutherfords nuclear model

Answer 9

they realised that atoms would collapse if the nuclear model was right because the cloud of electrons would’ve been attracted to the positively charged nucleus

Question 10

describe Niel Bohrs model

Answer 10

• electrons exist in fixed orbits
• each shell has a fixed energy
• when an electron moves between shells, EM radiation is emitted or absorbed
• radiation will have fixed frequency because the energy of shells is fixed