The document outlines key contributions to the discovery of electrons and protons by notable scientists including Sir William Crookes, J.J. Thomson, Eugen Goldstein, and Ernest Rutherford. It highlights Thomson's identification of electrons through cathode ray experiments and Rutherford's gold foil experiment which revealed the existence of protons and the atomic nucleus. The findings emphasize the nature of atomic structure and the behavior of subatomic particles under electric fields.

1. Discovery of Electrons and
Protons

2. Notable Scientist
Sir William Crookes (1832-1919)
British Chemist and Physicist
British National
Worked on vacuum and
Crookes tube and led
advancement in the
discovery of electrons

3. Notable Scientist
Sir Joseph John “J.J” Thomson ( 1856-1940)
English Physicist
British National
Credited for:
Discovery of Electrons
Nobel Prize in
Physics (1906)

4. Discovery of Electrons
Cathode Ray Tube

5. Important Observations:
 The beam were easily bent when
passing through a parallel plate
Bent towards the Positive Charge( +)
Bent away from the Negative (-)

6. Key Concepts:
Since the beam was bent so easily:
 Made up of a very light particles lighter
than a H atom
 He thought that there are even smaller particles
inside an atom.

7. Key Concepts:
Since the beam bent towards the positive
charged plate:
Since like charges repel and unlike charges
Attract
Beam carried a negatively charge particle
He called them “ELECTRONS”

8. Notable Scientist
Eugen Goldstein (1850-1930)
German Physicist
German National
Discovered: Anode Rays
Sometimes co-credited
on the discovery of
protons

9. Important Observations:

10. Notable Scientist
Ernest Rutherford (1871-1937)
British Physicist
New Zealander National
Nobel Prize in
Chemistry (1908)
Discovered the Protons
Gold Foil Experiment

11. Gold Foil Experiment

12. Important Observations:
 Alpha Particles (α) from Uranium were shot
directly to the gold foil
 Almost all of the α particles passed through
 Some α particle bent off-course at some
degree
 Least amount of α particle bounced back
from where it came.

14. Key Concepts:
Since the Nucleus was very small most α
particle completely missed them.
If some α particles comes close its positive
charge causes repulsion and bend them off
course.

15. Gold atoms were mostly empty-space
There must be something inside hard and
heavy

16. Key Concepts:
If the α particles makes a direct hit it
would bounce back
Since the nucleus is much heavier
than the α particles

17. Discovery of Protons
The particle that was inside the small lumps
that causes repulsion of α particles were
positively charge.
Then lately he discovered the particle that
causes the positive charge and called them
“ PROTONS”