A Level Chem Fundamental Particles

What are the names of the 4 people that are involved with the atomic theory?

J.J Thomson

John Dalton

Ernest Rutherford

Niels Bohr

Who was the man that first wrote about atoms?

John Dalton

How did John Dalton define an atom as?

The basic unit of matter

What was Dalton’s beliefs about an atom

-He thought atoms were spherical

-Different spheres or atoms constituted different elements

-He believed that atoms were fundamental units of matter

-He believed that atoms were invisible

What scientist came after John Dalton?

JJ Thompson

How many years after Daltons ideas did JJ make his own?

90

How does JJ Thompson’s idea differ from John Dalton’s idea?

JJ Discovered that atoms were divisible or visible.

Whereas John thought them to be invisible

What was JJ’s contribution to the atomic theory?

-He discovered that atoms were visible

-He discovered and measured the electron

-He measured the elctron to being several orders of magnitude lighter than an atom

-He proved that smaller particles than an atom exist

-He made the plum pudding model

What model did JJ Thompson create?

The plum pudding model

What was the plum pudding model?

A sphere of positively charged energy with spots of negatively charged electrons.

Which scientist came after JJ Thompson?

Ernest Rutherford

Did Ernest Rutherford prove or disprove JJ Thompson?

Disprove

How did Ernest disprove JJ Thompson?

-He fired alpha particles at a film of gold to test JJs theory

-If JJs theory was correct the alpha particles would be repelled by the gold.

-Most particles went straight through

What model did Ernest create?

The Nuclear Model

What did the nuclear model show?

-The atom was mostly empty space

-The model showed a positive nucleus with electrons orbiting it

How is the plum pudding model different from the nuclear model?

-The nuclear model has space in the atom

-The plum pudding has no space and is just a sphere of positive

-In the nuclear model the electrons are orbiting the nucleus

-The plum pudding model doesnt show any sign of orbit

Who came after Ernest Rutherford?

Niels Bohr

What did Niels Bohr believe?

-He thought that the nuclear model had a problem

-That the electrons should spiral into the nucleus

-He believed that when electrons move between orbits they must absorb electromagnetic radiation

What did Bohr create create?

The first quantum theory

What are the 3 Subatomic particles?

Protons Neutrons and Electrons

What is the mass and charge of a proton?

Mass- 1.0073amu

Charge- +1e

What is the mass and charge or a neutron?

Mass-1e

Charge- 0 no charge

What is the mass and charge of an electron?

Charge- -1e

Mass- 0.00055amu or 0

What is the definition of the atomic mass unit?

one twelfth the mass of a single carbon-12 atom