Lesson 1 (M3) & (M5) - Early ideas about matter Flashcards
What did early philosophers think matter was made up of?
Water, Earth, Fire, and air.
What was commonly accepted of matter back then?
That matter could be endlessly divided into smaller and smaller pieces.
What did Democritus believe?
He was the first to think that matter was not divisible.
He also believed that matter was made up of atoms that could not be created, destroyed, or further divided.
What did Aristotle believe?
He went against Democritus because he believed that empty space could not exist.
How did Aristotle challenge Democritus?
Aristotle asked Democritus what held the universe together.
In other words, what held/bonded atoms together.
Democritus could not answer.
What did John Dalton do?
John Dalton began the development of the modern atomic theory.
He also revived Democritus’s ideas based on scientific research.
What are the points of Dalton’s atomic theory?
1- Matter is made up of extremely small particles called atoms.
2- Atoms are indivisible and indestructible.
3- Atoms of a given element are identical in size, mass, and chemical properties.
4- The atoms of a specific element are different than another element.
5- Different atoms combine in fixed ratios to form compounds.
6- In reactions, atoms are separated, combined, or re-arranged.
What is the law of conversation of mass?
The law of conversation of mass states that in a reaction, mass could not be created nor destroyed.
What did J.J Thompson discover?
JJ Thompson is credited with the discovery of the electron, and its negative charge.
What was JJ Thompsons model and what did it contain?
The plum pudding model.
It had a spherical shape, which was uniformly distributed positive charge, where the electrons resided.
What did Rutherford study and find?
Rutherford studied how positively charged alpha particles interacted with solid matter.
He concluded that JJ Thompsons model was incorrect because it could not explain the result of his gold foil experiment.
