Scientists(Complete) Flashcards
What did Democritus do?
Came up with the idea of atoms.
Atomos in greek.
What did Boyle do?
Boyles law-V=1/P x constant.
Elements can not be broken down into anything simpler.
What did Lavoisier do?
Listed the known elements.
Law of conservation of mass- matter can’t be created nor destroyed in a chemical reaction.
What did Davy do?
Discovered electrolysis.
Used electrolysis to find many elements- K, Na, Ca
What did Dalton do?
Atomic Theory:
All matter is composed of tiny particles called atoms.
Atoms are unique.
They are indivisible and indestructible.
They combine in whole numbers.
Chemical reactions involve the rearrangement of these atoms.
What did Doberenier do?
Grouped 3 elements with similar properties where the middle one is intermediate- called them triads. Example: Chlorine- Gas- 35.5-Green Bromine- Liquid- 90- Brown Iodine- Solid- 127- Purple/Black
What did Newlands do?
Discover the law of octaves.
Arranged elements in order of atomic mass.
Properties repeat every 8th element.
What did Mendeleev do?
Arranged elements so they would fit into their property space rather than weight.
Left gaps for elements that were yet to be discovered.
What did Moseley do?
Arranged elements by atomic number- positive charge of nucleus.
What did Crookes do?
Maltese cross experiment.
Discovered cathode rays.
What did Thompson do?
Deflected cathode rates with charged plates and discovered that they were negative.
Called these particles electrons.
Name was proposed by George Stoney of UCG.
Plum pudding model.
Worked out the charge to mass ratio.
What did Millikan do
Oil drop experiment- 1909.
Measured the charge on an electron.
What did Rutherford do?
Fired alpha particles at gold foil.
99% passed through- atom mainly empty space.
Some were deflected- centre positive.
Some bounced back-nucleus very dense.
Concluded:
Atoms consist of small dense positive centre called a nucleus.
Called positive particles protons.
What did Bohr do?
Discovered that electrons orbit the nucleus in shells.
Energy levels are fixed or quantised.
What did Chadwick discover?
Discover neutrons.
