Unit 1 Flashcards
(12 cards)
Who proposed the existence of indivisible/incuttable particles, called atoms that were the building blocks of matter? When was it?
Democritus (440 BC)
Who didn’t believe in the concept of atoms and proposed the idea of 4 key elements (fire, water, air and earth)? When?
Aristotle (440 BC)
Who developed quantitative experimentation in search of transmutations (ways of measuring things, glassware, distillation techniques)?
Alchemists
Who developed the atomic theory in the 1800s?
John Dalton
What is the Atomic Theory?
- All matter is made of tiny particles (atoms)
- Atoms are indivisible and indestructible
- atoms are solid spheres
- atoms of different elements differ in size and colour
Who discovered electrons?
JJ Thomson
Who is connected to the “Plum Pudding model?”
JJ Thomson
JJ Thomson year
1897
What did JJ Thomson used to show that electrons existed?
Cathode ray tube
Who is known for the gold foil experiment with alpha particles? When?
Rutherford (1909)
What was the gold foil experiment? What did it prove?
Rutherford shot an alpha particle beam at a piece of gold foil. He noticed that some light went through and that some light deflected in different directions. It proved that atom’s mass is located at the centre of an atom
How do you find the Average Atomic Mass?
The sum of (the elements isotope that is multiplied by the decimal of the percentage of how much is present)
