Fundamental particles

what year and what did the greek philosopher’s invent?

5th century BC

-Democritus and Lecippus believed that you would end up with a particle that would not split any futher

-invisible

what did robert boyle discover?

Substances could not be made simpler- chemical elements

what did john dalton discover and when?

1800s

-atoms are tiny particles making up elements, atoms of an element are the same, indivisible atoms, atoms of different elements have different masses

Henri Bacqueral

discovered radioactivity, showed that particles come from inside of atom, so not indivisable

JJ Thompson

discovered electron with cathode rays. The negative electrode inside cathode ray tubes emitted electrons. The particles had a negative charge, both magnetic and electric fields, deflected particles, small mass

Geiger and mardsen

directed alpha particles at a thin sheet of gold foil and measured angle of deflection

Ernst rutherford

Discovered proton in 1918

most were deflected, small percent deflected at a large angle, very small percent deflected backwards, concluded a positive charge, dense nucleus that contained most of the mass (cloud of negative charge)

Niel Bohr year and what?

atoms consisted of a small positively charged nucleus that was surrounded by electrons on electron shells at fixed energy levels and their movement from one shell to next explained how atoms absorbed and gave out light.

erwin schrodinger

discovered that electrons had some of the properties as waves, which allowed to predict the behaviour of subatomic particles

james chadwick

discovered neutron, same mass as proton, neutral, uncharged

what are protons and neutrons sometimes called?

nucleons

describe the arrangement of subatomic particles

The protons and neutrons are found in the centre of the atom held together by a strong nuclear force. The nucleus is surrounded by electrons on electron shells at fixed energy levels.