Chemistry - History of Chemistry Flashcards
What did Democritus propose?
If you break something into the smallest piece it can get, that is the atom of the item.
(i.e. if a piece of paper is ripped to the smallest piece, that piece is the atom of paper)
Who disagreed with Democritus?
Aristotle
Who proposed that objects are made of four elements (fire, water, earth, and air)?
Aristotle
What did John Dalton propose in his Atomic Model?
- Every element has its own unique
atom and vice versa - Compounds are combos set in
numbers
Who FIRST invented the symbolizes for elements (that were later changed?)
John Dalton
Who believe that atoms are solid spheres with protons and neutrons?
John Dalton
What did Michael Faraday discover?
Atoms could gain electrical charges
Describe the changes made by Faraday to Dalton’s theory.
- Matter must contain positive and
negative charges. - Opposite charges attract, and like
charges repel. - Atoms combine to form the
particles of a compound because
of the electrical attraction
between charged atoms
What is the “plum pudding” model and who created it?
- Electrons are embedded in
positive and negative matter in
the “plum pudding” model. - Created by JJ Thomson
What did JJ Thomson discover?
Electrons
Describe what Earnest Rutherford proposed.
- Believed that electrons orbited the
center (the nucleus) , which had
protons and
neutrons - There was empty space between
the nucleus and electrons
What did Berzelius do?
He changed the symbols for elements. (Previously made by Dalton)
Describe the symbols made by Berzelius.
- If an element is the first to start
with a certain letter, the first letter
gets capitalized. - If another element starts with the
same letter, the second letter
lowercase is added. - Some elements have Latin names.
Who discovered the Periodic Table?
Dmitri Mendeleev
Why was Mendeleev’s Periodic Table useful for chemists?
It has a predictable feature.
